Abstract

For the purpose of solving the above problems, the present invention includes: transmission/reception means provided in a flow path for performing transmission/reception using a state change of fluid; repetition means for repeating the transmission/reception; time measurement means for measuring a time of propagation repeated by the repetition means; flow rate detection means for detecting a flowrate based on a value of the time measurement means; and number-of-times change means for changing to a predetermined number of repetition times. With such a structure, an influence caused by a variation of a flow can be suppressed pressed by changing the number of repetition times so as to be suitable for a variation. As a result, reliable flow rate measurement with a high accuracy can be achieved.

Description

Flowmeter

The application is the dividing an application for the Chinese patent application of " flowmeter " that 00809439.X, the applying date be on 06 23rd, 2000 and denomination of invention for application number.

Technical field

The present invention relates to a kind of flowmeter that is used to measure liquid or air rate.Even the invention still further relates to when having pressure or temperature variation also the device that can measure flow rate value in mode accurately.

Background technology

Traditionally, such flowmeter is known, and for example Japan treats just to have put down in writing among the publication No.9-15006 a kind of like this flowmeter.Shown in Figure 64, this flowmeter comprises: be the time interval first sample time that sample procedure 2, this program are used for to be scheduled to, and reads measured value from the analogue flow rate sensor 1 of measurement gas flow rate; Spent gas amount calculation procedure 3, this program is used for the flow rate at preset time calculation consumption gas; Mean computation routine 4, this program are used in one section preset time section to be second sample time in time interval, calculate the mean value of the measured value that reads from the analogue flow rate sensor in first sample time; Pressure change frequency appraisal procedure 5, this program are used for the change frequency according to the output valve assessment pressure of flow sensor; And the RAM6 that is used as storer, here, reference number 7a representative is used for the CPU of executive routine, and reference number 7b representative is used for the ROM of stored routine.In this structure, carry out measuring process, so that a change frequency cycle that predetermined Measuring Time is equaled or be longer than pump, or several times that should the cycle.Averaging is so that avoid the variation of flow rate.

As another conventional example, Japan treats that invention disclosed also is known among the publication No.10-197303.Shown in Figure 65, this flowmeter comprises: the flow rate detection device 8 that is used to detect flow rate; Be used to detect the frequency detecting device 9 of fluctuations in discharge frequency; And Measuring Time setting device 10, the Measuring Time that this device is used for detecting flow rate is set to the time of the one-period that approximately is several times as much as change frequency.Here, reference number 11 is represented the flow rate calculation device; Starter gear is measured in 12 representatives; 13 representation signal treating apparatus; And 14 represent flow rate.In this structure, measure flow rate according to changing waveform frequency, obtain correct flow-rate measurement value whereby in the short period of time.

As another conventional example, Japan treats that invention disclosed also is known among the publication No.11-44563.Shown in Figure 66, this flowmeter comprises: the flow rate detection device 15 that is used to detect flow rate; The change detecting device 16 that is used for tracer liquid flow rate variation waveform; Impulsive measurement device 17, this device are used for when the variable componenent that changes waveform approaches zero, make the flow rate detection device begin to measure; And the flow rate calculation device 18 that is used to handle the signal that comes from the flow rate detection device.Here, reference number 19 representation signal treatment circuits; 20 represent time measuring circuit; 21 represent delta circuit; 22 represent transmission circuit; 23 represent comparator circuit; 24 represent amplifying circuit; 25 representation switch; The enabling signal circuit is measured in 26 representatives; And 27 represent starter gear; 28 represent stream.In this structure, measure the flow rate that approaches to change the wave-average filtering value, obtain correct flow-rate measurement value whereby in the short period of time.

As a conventional example again, Japan treats that invention disclosed also is known among the publication No.8-271313.Shown in Figure 67, whether checking (30) flow rate value has been measured in (29) at flow sensor is detected.Up to having verified that flow rate is detected, could carry out this process, and continue the measurement of flow sensor.In case found flow rate, determined whether flow rate Q is equal to or higher than predetermined value (31).When flow rate Q is equal to or higher than predetermined value (31), determine again whether the pressure variation surpasses predetermined value Cf (32).When pressure changes not above predetermined value Cf, carry out measuring process 34 with the piezo film sensor of fluidic flowmeter.When pressure changed above predetermined value Cf, checking pressure changed whether surpass second predetermined value (33).When pressure changes above second predetermined value, carry out measuring process (34) with the piezo film sensor of fluidic flowmeter.When pressure changes not above second predetermined value, carry out measuring process (29) with flow sensor.

Shown in Figure 68, ultrasonic converter 51 and 52 is configured in the flow-rate measurement unit 50, so that opposite with flow direction.Control module 53 starts timer 54, simultaneously transmission signals is exported to drive circuit 55.A ultrasound wave spreads out of from ultrasonic converter 51, and transducer 51 receives the output of drive circuit 55.This ultrasound wave is received by ultrasonic converter 52.The receiving test circuit 56 that receives the output of ultrasonic converter 52 detects this ultrasound wave and timer 54 is stopped.By this operating process, the time period (t1) of that time when this ultrasound wave is detected by ultrasonic converter 52 that time of measuring ultrasound wave when ultrasonic converter 51 spreads out of.Secondly, according to the signal operation on-off circuit 58 from control module 53, so that drive circuit 55 is linked to each other with ultrasonic converter 52, receiving test circuit 56 links to each other with ultrasonic converter 51.In this state, carry out hyperacoustic transmission and reception again, so that the time period (t2) of that time when this ultrasound wave is detected by ultrasonic converter 51 that time of measuring ultrasound wave when ultrasonic converter 52 spreads out of.According to these two travel-times (t1) and (t2), computing unit 57 calculates flow rate by the difference between these two travel-time inverses.

As a conventional example of such flowmeter, Japan treats that invention disclosed is known among the publication No.6-269528.

Yet, in above-mentioned these conventional first that invent, utilize the measurement of average value specific gas flow rate.Therefore, need measure for a long time, so that obtain reliable mean value, the result, such flow-rate measurement can not be finished in the very short time.In second of above-mentioned these conventional inventions, measurement can not overcome the variation of frequency.In third and fourth conventional invention, be used to measure flow rate method must according to pressure/pressure change lack and change, and must provide two kinds of devices, i.e. device for pressure measurement and flow metering device.In first to fourth invention, when appearance is unusual, or just can not measure, or promptly allow to measure, accuracy is also very low.

Moreover, in above-mentioned these conventional structures, when received signal, if the noise of existence and survey frequency or ultrasonic transmission Frequency Synchronization, then this noise same superimposed on signal when identical always in the travel-time.This noise is taken as measuring error and counts, and therefore can not carry out correct measurement.And when because temperature variation etc. is former thereby when the travel-time was changed, the phase of noise stack place had also changed, thus, measuring error changes.In addition, owing to determine the resolution of measurement according to the resolution of timer 54, so only make these measured value equalizations simply, can not increase the accuracy of measurement.Like this, need to increase the resolution of timer 54, so that need the measurement of resolution.So that when having higher frequency, will occur variety of issue when the operation clock that increases timer 54, for example power consumption increases, and high frequency noise increases, and circuit size increases.Like this, an existing target is to utilize the timer of operating under low frequency to increase the resolution of measurement, so that increase the accuracy of measuring.

In the 5th conventional invention, a deferred mount is between control module and driving circuit, and the amount of change delay, so that avoid reflection wave.For example this mode has reduced the effect of reflection wave.The noise that is produced during for example, owing to ultrasonic transmission makes the ultrasonic converter vibration of receiver side.So the variation of signal-reception detection time can not reduce, and this variation is echoed to be added to and is caused on the ultrasonic signal owing to this vibration.

The present invention seeks to solve above these problems.Therefore, first purpose of the present invention is, by utilizing software rather than utilize other variable pick-up unit change detected frequency that best number of times according to the variation duplicate measurements of flow is set, and changes the number of times that repeats in succession.And, even seek when pressure variations and change frequency change, also can be in the very short time with a kind of reliably accurately mode measure flow rate.Second purpose of the present invention is to finish the flow-rate measurement of pin-point accuracy following moment: i.e. the variation that comes detected transmission/receiving trap without other variable pick-up unit by switch, and carry out measuring process synchronously with variable.The 3rd purpose of the present invention be, though in measuring process, occur any when unusual, also can to measure the monitoring device fast detecting this unusual and suitably handle measurement result and come pin-point accuracy ground measurement flow rate by utilizing.The 4th purpose of the present invention be, by utilizing instantaneous flow rate measurement mechanism and digital filtering device, can be in the very short time with a kind of reliably accurately mode carry out flow-rate measurement.The 5th purpose of the present invention is, even also can measure flow rate value in pin-point accuracy ground when temperature changes.

Disclosure of the present invention

In order to address the above problem, flowmeter of the present invention comprises: be configured in the stream, be used to utilize the state variation of fluid to carry out the transmission of transmission; The duplicating device that is used for the repetition transmission; Be used for Measuring Time or by the time measurement device of the propagation that duplicating device repeated; Be used for detecting the flow rate detection device of flow rate according to the measured value of time measurement device; And the number of times modifier that is used to change predetermined multiplicity.Multiplicity can change to the number of times that is fit to variable, so that eliminate the influence of fluctuations in discharge.As a result, can access the reliable flow-rate measurement of pin-point accuracy.

This flowmeter comprises a pair of transmission, and this device utilizes the state variation of hyperacoustic propagation as fluid.Like this, by utilizing ultrasonic transmission/receiving trap, even when fluid generation state changes, also can carry out hyperacoustic propagation.And, by multiplicity being changed to the number of times that is fit to variable, can access the reliable flow-rate measurement of pin-point accuracy.

This flowmeter comprises transmission, and this device utilizes the state variation of calorie spread as fluid.Like this, by utilizing heat delivered/receiving trap, even when fluid generation state changes, also can carry out calorie spread.And, by multiplicity being changed to the number of times that is fit to variable, can access the reliable flow-rate measurement of pin-point accuracy.

This flowmeter comprises: the elapsed time pick-up unit, be used to detect the information midway in travel-time, and this travel-time is by the duplicating device replication; Frequency detecting device is used for detecting the flow rate variation frequency from the information of elapsed time pick-up unit; And the number of times modifier, be used to Measuring Time is set so that make it be several times as much as the frequency that detects by frequency detecting device basically.Like this, just need not the pick-up unit that provides special.Before carrying out flow rate detection, change detected frequency from the information midway of time measurement device, and Measuring Time is set, make it be several times as much as the one-period of frequency.As a result, can access the reliable flow-rate measurement of pin-point accuracy.

This flowmeter comprises: data hold is used to preserve one or more at least travel-times that repeat transmission that obtained by the elapsed time pick-up unit; And frequency detecting device, be used for detecting frequency by the data of data hold preservation and measured travel-time data are compared.The time measurement information of each process all can and compare by the data hold preservation, can detect frequency whereby.

Number of operations modifier in predefined procedure.Because number of run modifier when carrying out prior defined procedure only, so this processing procedure of number of times modifier is limited to required minimizing.So power consumption significantly reduces.

Number of run modifier in each predetermined flow-rate measurement process.Like this, in each predetermined flow-rate measurement process, change multiplicity, whereby, even when fluctuations in discharge is very big, also can measure flow rate in pin-point accuracy ground.

Number of run modifier before the flow-rate measurement process.Carry out flow-rate measurement pre-determined number before because multiplicity is set to, therefore mode pin-point accuracy ground carries out flow-rate measurement reliably.

Prior defined procedure comprises: record the operation of device unusually, be used for measuring the unusual of flow rate from measured flow rate; And the flow rate management devices, be used for from the user mode of measured flow rate management flow rate.Because only change multiplicity when execute exception records process and flow rate management process, the process that therefore changes multiplicity is limited to required minimizing.So, can reduce power consumption.

Multiplicity by the resulting frequency adjustment of frequency detecting device can be used for next flow-rate measurement process.Because this multiplicity can be used in the next measuring process, therefore need not to carry out the duplicate measurements of frequency detecting.Like this, can reduce power consumption.

When measured flow rate is lower than predetermined flow rate, the number of run modifier.Owing to only when flow rate is equal to or less than predetermined flow rate, just change multiplicity, and when flow rate is high, do not carry out this process, therefore can reduce power consumption.

Flowmeter of the present invention comprises: transmission, and this is configured in the stream, is used to utilize the state variation of fluid to carry out transmission; Time measurement device is used to measure the travel-time by the transmission transmission; The flow rate detection dress, this device is used for detecting flow rate according to the measured value of time measurement device; The variable pick-up unit is used for measuring by the caused stream variation of transmission; And measuring and controlling, when being used to be synchronized with the variograph of variable pick-up unit and start measurement.Owing to can utilize transmission to measure the variation of stream, therefore need not to provide another to be used for the sensor of detection variable.Like this, the size of flowmeter can be reduced, and the designs simplification of stream can be made.In addition, even when occurring changing, also can measure flow rate with reliable mode pin-point accuracy ground at short notice.

This flowmeter comprises a pair of transmission, and this device utilizes the state variation of hyperacoustic propagation as fluid.Like this, but utilize the state variation of ultrasonic transmission/receiving trap test fluid.Therefore, the timing that can be synchronized with variable starts measurement.As a result, can measure flow rate with reliable mode pin-point accuracy ground.

This flowmeter comprises transmission, and this device utilizes the state variation of calorie spread as fluid.Like this, but utilize the state variation of heat delivered/receiving trap test fluid.Therefore, the timing that can be synchronized with variable starts measurement.As a result, can measure flow rate with reliable mode pin-point accuracy ground.

This flowmeter comprises: first vibrating device and second vibrating device, these devices be configured in the stream, be used for the transmission ultrasound wave; Switchgear is used for the transmission operation of switch first vibrating device and second vibrating device; The variable pick-up unit, the pressure that is used for detecting in the stream of at least one device of first vibrating device and second vibrating device changes; Time measurement device is used to measure the hyperacoustic travel-time by first vibrating device and the second vibrating device transmission; Measuring and controlling, be used for following situation is carried out control: promptly, when the output of variable pick-up unit shows predetermined variation, measurement mechanism is measured the first Measuring Time T1 from first vibrating device of stream upstream one side to the propagation of second vibrating device of stream downstream one side, and when the output demonstration of the variable pick-up unit variation opposite with predetermined variation, measurement mechanism is measured the second Measuring Time T2 from second vibrating device of stream downstream one side to the propagation of first vibrating device of stream upstream one side.Owing to be to measure in that time of the change of pressure variations counter-rotating, so pressure can drift about when changing mutually with meter mutually.As a result, can offset the measuring error that is caused by the pressure variation.

This flowmeter comprises: measuring and controlling, be used for following situation is carried out control: promptly, when showing predetermined variation, the output of variable pick-up unit begins the measurement of the first Measuring Time T1, when the output demonstration of the variable pick-up unit variation opposite with predetermined variation, begin the measurement of the second Measuring Time T2, and following situation carried out control: promptly, in next is measured, when the output demonstration of the variable pick-up unit variation opposite with predetermined variation, begin the measurement of the first Measuring Time T1, when the output of variable pick-up unit shows predetermined variation, begin the measurement of the second Measuring Time T2; And flow rate calculation device, be used for by make first flow rate and second flow rate in succession equalization calculate flow rate, and first flow rate is by utilizing first previous Measuring Time T1 and the second previous Measuring Time T2, alternately change the startup of measuring simultaneously and obtain, and second flow rate to be the first Measuring Time T1 by utilizing next and the second Measuring Time T2 of next obtain.Like this, change the timing of measurement as mentioned above, so that the first Measuring Time T1 and the second Measuring Time T2 are measured.As a result, even when the pressure variation is asymmetric between high-pressure side and low-pressure side, also can offset the influence that this pressure changes.

This flowmeter comprises the duplicating device that is used for repeatedly carrying out transmission.Like this, can averaging by increase measuring number of times, the result can carry out reliable flow-rate measurement.

This flowmeter comprises the duplicating device that is used for repeatedly carrying out transmission in the time period that is several times as much as a variable cycle.Like this, can make pressure change equalization by measuring according to change frequency.As a result, can measure stable flow rate.

This flowmeter comprises duplicating device, be used for when the output of variable pick-up unit shows predetermined variation, the measurement of beginning transmission, and repeat thisly to have hyperacoustic transmission and measure, when the output demonstration of the variable pick-up unit variation identical with predetermined variation till.Like this, the frequency that pressure changes is all deferred in the beginning of measurement and termination.Therefore, can measure change frequency and make pressure change equalization.As a result, can measure stable flow rate.

This flowmeter comprises the selecting arrangement that is used for the following situation of switch: a kind of situation is, first vibrating device and second vibrating device are used for hyperacoustic transmission, and a kind of situation is that first vibrating device and second vibrating device are used for the detection that pressure changes.Like this, at least one device in first vibrating device and second vibrating device can be used for pressure detection.As a result, can obtain flow-rate measurement and pressure survey simultaneously.

This flowmeter comprises the variable pick-up unit, is used to detect near the one-component of the AC compounent of the variable waveform zero.Like this, near the null component of this variable, detect a variable, measure so in a time, near null variable, start, so that carry out flow-rate measurement.Therefore, by carrying out flow-rate measurement in the little time, stablize even when flow changes, also can make to measure at variable.

This flowmeter comprises: frequency detecting device is used for the signal frequency of detection variable pick-up unit; And measuring and controlling, this device only when the frequency that is detected by frequency detecting device is preset frequency, just starts and measures.Like this, by only when frequency is preset frequency, just starting measurement, can when predetermined variation occurring, carry out measurement.As a result, can measure stable flow rate.

This flowmeter comprises detecting cancels device, and this device can start measurement automatically after a predetermined amount of time when not detecting the signal of variable pick-up unit.Like this, even after changing disappearance, measure flow rate in the time of also can reaching at the fixed time automatically.

Transmission and first and second vibrating device comprise piezoelectric sender.Like this, when using piezoelectric sender, ultrasound wave can be used for transmission, can detected pressures change simultaneously.

Flowmeter of the present invention comprises: transmission, this device are configured in the stream, are used to utilize the state variation of fluid to carry out transmission; Duplicating device is used for the signal propagation that repetition is carried out by transmission; Time measurement device, the travel-time that is used for measuring the repetitive process of carrying out by duplicating device; The flow rate detection device is used for detecting flow rate according to the measured value of time measurement device; The variable pick-up unit is used for detecting the fluctuations in discharge of stream; Measuring and controlling is used for controlling above each device that these install; And the measurement monitoring device, be used for each device of above these devices of monitoring automatically.Like this, when the flow in the stream changes, can utilize simultaneously and measure monitoring device fast detecting abnormal conditions according to this measure of the change flow rate.Therefore, can correctly carry out the processing of abnormal conditions and make measured value stable.As a result, can measure flow rate in pin-point accuracy ground, and improve measuring reliability.

This flowmeter comprises a pair of transmission, and this device utilizes the state variation of hyperacoustic propagation as fluid.Owing to used ultrasound wave, even therefore when flow changes, also can carry out flow-rate measurement.And, can utilize the measurement monitoring device correctly to carry out the processing of abnormal conditions.As a result, can improve measuring reliability.

This flowmeter comprises transmission, and this device utilizes the state variation of the propagation of heat as fluid.Owing to used calorie spread, even therefore when flow changes, also can carry out flow-rate measurement.And, can utilize the measurement monitoring device correctly to carry out the processing of abnormal conditions.As a result, can improve measuring reliability.

This flowmeter comprises: a pair of transmission, this device be configured in the stream, be used for the transmission ultrasound wave; Duplicating device, the signal that is used for the repetition transmission is propagated; Time measurement device is used for measuring hyperacoustic travel-time of repetitive process of being carried out by duplicating device; The flow rate detection device is used for detecting flow rate according to the measured value of time measurement device; The variable pick-up unit is used for detecting the fluctuations in discharge of stream; Measuring and controlling is used for controlling above each device that these install; And measurement monitoring device, be used for monitoring the abnormal conditions of enabling signal and the abnormal conditions in the end signal, the first output signal place of the variable pick-up unit of enabling signal after the turn signal of measuring and controlling wherein, instruct ultrasonic transmission to begin, end signal instructs hyperacoustic transmission repetitive process to finish at the second output signal place of variable pick-up unit.Like this, when the flow in the stream changes, can be synchronized with change frequency and carry out measurement, and utilize and measure monitoring device detection abnormal conditions.Therefore, can measure flow rate in pin-point accuracy ground, and obtain reliable measured value.In addition, can correctly carry out the processing of abnormal conditions, and improve the reliability of measured flow rate value.

This flowmeter comprises the measurement monitoring device, when being used for not producing enabling signal in one period schedule time after measuring and controlling turns to, instructs ultrasound wave to begin transmission after one period schedule time.Like this, even when not changing and in the preset time section, being not activated signal, also can measure flow rate, and avoid data degradation in each schedule time.

This flowmeter comprises the measurement monitoring device, when being used for not producing enabling signal in one period schedule time after measuring and controlling turns to, instructs ultrasound wave to begin transmission after one period schedule time.And be used to carry out the measurement of predetermined multiplicity.Like this, even when not changing and in the preset time section, being not activated signal, also can carry out the flow-rate measurement of predetermined number of iterations, and avoid data degradation in each schedule time.

This flowmeter comprises the measurement monitoring device, when being used for not producing enabling signal in one period schedule time after measuring and controlling turns to, just measures when the next one of measuring and controlling turns to.Till next one measurement turns to, can not carry out unnecessary measurement by pausing operation, reduce power consumption whereby.

This flowmeter comprises the measurement monitoring device, when being used for not producing end signal in one period schedule time after enabling signal, stops ultrasonic reception.Because ultrasonic reception is forced to stop, therefore when waiting for end signal, can not suspend measurement.Like this, measurement can proceed to next process, and can carry out stable measuring operation.

This flowmeter comprises the measurement monitoring device, when this device does not produce end signal in one period schedule time after enabling signal, can stop ultrasonic reception and export enabling signal again.Because ultrasonic reception is forced to stop, therefore when waiting for end signal, can not suspend measurement.And enabling signal is exported again, thereby remeasures.Like this, can carry out stable measuring operation.

This flowmeter comprises the measurement monitoring device, is used for when abnormal conditions appear in multiplicity, stops the transmission process.Because measurement appears having stopped when unusual in multiplicity, therefore have only the data of pin-point accuracy can be used in and carry out flow-rate measurement.

This flowmeter comprises the measurement monitoring device, first multiplicity that this device will be used to measure compares with second multiplicity that is used to measure, and when the difference between first and second multiplicity is equal to or greater than pre-determined number, export enabling signal once more, wherein in the measurement of using first multiplicity, ultrasound wave comes out to transmission first device of transmission from this, and received by second transmission, and in the measurement of using second multiplicity, ultrasound wave transmits from second transmission, and is received by first transmission.Like this, when these two multiplicity obviously not simultaneously, can measure again, can have the measurement of the pin-point accuracy of steady change frequency whereby.

This flowmeter comprises duplicating device, be used to be provided with multiplicity, equate with second multiplicity that is used to measure for use in first multiplicity of measuring, wherein in the measurement of using first multiplicity, ultrasound wave comes out to transmission first device of transmission from this, and is received by second transmission, and in the measurement of using second multiplicity, ultrasound wave transmits from second transmission, and is received by first transmission.Like this, by utilizing identical multiplicity, even when change frequency is unstable, also can be scheduled to the measurement of flow rate.

This flowmeter comprises the measurement monitoring device, is used to monitor the number of times that enabling signal is exported once more, thereby makes the output of enabling signal be confined to pre-determined number or number of times still less, so that the output of enabling signal can forever not repeated down.Like this, by the number of times that restriction remeasures, can stop measuring process forever to continue.As a result, can carry out stable flow-rate measurement.

This flowmeter is measured flow rate by the difference between the inverse in travel-time, repeatedly repeats hyperacoustic transmission simultaneously.Like this, when using ultrasound wave, can under not by the situation of the influence of the change frequency in the stream, carry out transmission.And, measure flow rate by the difference of the inverse in the travel-time of being measured, repeat transmission simultaneously, whereby, even can measure a macrocyclic variation by some units of one-period.In addition, the difference in the travel-time that is caused by variable can utilize difference reciprocal to offset.

Flowmeter of the present invention comprises: the instantaneous flow rate pick-up unit is used to detect instantaneous flow rate; Device is determined in fluctuation, and whether be used for measuring flow rate value has pulse; And at least one or a plurality of stable flow rate calculation element, be used for determining that according to fluctuation the measurement result of device utilizes different device to calculate flow rate value.Like this, by measuring variation and the switch flow rate calculation device in institute's flow measurement rate, can calculate flow rate in reliable mode according to variable quantity by a flow metering device.

Flowmeter of the present invention comprises: the instantaneous flow rate pick-up unit is used to detect instantaneous flow rate; Filter processing is used to carry out the digital filtering processing of flow rate value; And stable flow rate calculation element, be used to utilize filter processing to calculate flow rate value.Like this, when carrying out digital filtering when handling, can carry out the computation process that is equal to mutually with homogenization process, and need not to utilize a large amount of storeies to come storage data.And, can by change a variable for example filter factor adjust filtering characteristic.

This flowmeter comprises stablizes the flow rate calculation element, is used for utilizing the digital filtering treating apparatus to calculate a stable flow rate value when fluctuation determines that device mensuration has pulse.Like this, when pulse occurs, select the sharp cut-off filtering characteristic,, and only when pulse occurring, just carry out Filtering Processing so that bigger pulse stable state is provided.

Fluctuation determines whether the amplitude of variation of device mensuration flow rate value is equal to or greater than predetermined value.Like this, can measure pulse, adjust Filtering Processing according to the amplitude of variation of pulse whereby according to the amplitude of variation of pulse.

Filter processing is adjusted filtering characteristic according to the amplitude of variation of flow rate value.Because filtering characteristic changes according to the amplitude of variation of flow rate value, therefore can the rapid adjustment filtering characteristic, so that abundant relaxation filtering characteristic, this feature make to change and hour to change according to the variation of flow rate, and when changing greatly, select the sharp cut-off filtering characteristic, so that can obviously reduce the flow rate variation that causes owing to pulse.

Have only when the flow rate value that is detected by the instantaneous flow rate pick-up unit is low, just carry out Filtering Processing.Because only when flow rate is low, just carry out Filtering Processing, but the therefore variation of fast processing flow rate when flow rate is high, and the influence of fluctuations that is caused when flow rate is low is obviously reduced.

Filter processing is adjusted filtering characteristic according to flow rate value.Because filtering characteristic changes according to flow rate value, therefore only when flow rate is low, just carry out Filtering Processing, and variation that can the fast processing flow rate when flow rate is high, and the influence of fluctuations that is caused when flow rate is hanged down is obviously reduced.

Filter processing is adjusted filtering characteristic according to the flow rate time interval of instantaneous flow rate pick-up unit.Like this, provide interval to change filtering characteristic, can measure the variation that reduces the relaxation filtering characteristic at interval in short-term, and when measuring interval length, reduce the variation of sharp cut-off filtering characteristic according to the flow rate detection time.

This flowmeter comprises filter processing, and this device is adjusted filtering characteristic when flow rate is high, so that the frequency cutoff of filtering characteristic becomes higher, and is adjusting filtering characteristic when flow rate is low, so that filtering characteristic has lower cutoff frequency.Like this, response characteristic increases when flow rate is high, and fluctuation reduces when flow rate is low.

Adjust filtering characteristic, so as by the amplitude of variation of the flow rate value of stablize calculating of flow rate calculation element in predetermined range.Because filtering characteristic is adjusted,, therefore can reduces the variation of flow rate, thereby always be equal to or less than predetermined value so that make amplitude of variation in predetermined range.

Utilize the ultrasonic flow meter of ultrasound examination flow rate to be used as the instantaneous flow rate pick-up unit.Like this, by utilizing ultrasonic flow meter, even when bigger flow rate variation occurring, also can measure instantaneous flow rate.Like this, by this flow rate value, can calculate a stable flow rate.

Flowmeter according to heat is used as the instantaneous flow rate pick-up unit.When the flowmeter that utilizes according to heat, even when bigger flow rate variation occurring, also can measure instantaneous flow rate.Like this, by this flow rate value, can calculate a stable flow rate.

Flowmeter of the present invention comprises: the flow-rate measurement unit, treat fluid measured this unit of can flowing through; A pair of ultrasonic converter, this converters are used for the transmission ultrasound wave in the flow-rate measurement unit; Be used to drive the drive circuit of one of ultrasonic converter; The receiving test circuit that links to each other, is used to detect ultrasonic signal with another ultrasonic converter; Be used to measure the timer in the travel-time of ultrasonic signal; The control module that is used for the Control Driver circuit; Be used for calculating the computing unit of flow rate by the output of timer; And be used for the cyclical variation device that order changes the driving method of drive circuit, wherein control module control cycle changeable device so that the frequency of flow-rate measurement is changed successively, thereby avoids survey frequency to keep constant.Like this, when receiving ultrasound wave, the noise synchronous with survey frequency or hyperacoustic transmission frequency can not occur mutually same, but disperseed.Therefore, can reduce measuring error.

Flowmeter of the present invention comprises: the flow-rate measurement unit, treat fluid measured this unit of can flowing through; A pair of ultrasonic converter, this converters are used for the transmission ultrasound wave in the flow-rate measurement unit; Be used to drive the drive circuit of one of ultrasonic converter; The receiving test circuit that links to each other, is used to detect ultrasonic signal with another ultrasonic converter; Control module, this unit are used for pre-determined number ground Control Driver circuit, drive ultrasonic converter once more so that respond the output of receiving test circuit; Be used for pre-determined number ground and measure the timer in elapsed time; Be used for calculating the computing unit of flow rate by the output of timer; And the cyclical variation device that is used for changing in proper order the driving method of drive circuit, wherein the output for the response receiving test circuit receives, control module changes the cyclical variation device when each reception of receiving test circuit detects, so that make frequency not keep constant.Like this, can in a flow-rate measurement cycle, repeatedly set the next operating cycle property changeable device in ground in order to measure.As a result, noise in measurement result, and can be accessed reliable measurement result by homogenizing dispersedly.

Output a plurality of output signals in cyclical variation device switch ground with different frequency; And control module changes the frequency configuration of cyclical variation device when each the measurement, thereby changes the driving frequency of drive circuit.Like this, by changing driving frequency, can change by frequency change time corresponding to receive and detect sequential with drive signal.Like this, when ultrasound wave was received, the noise synchronous with survey frequency or hyperacoustic transmission frequency can not occur mutually same, but disperseed.Therefore, can reduce measuring error.

The output of cyclical variation device has same frequency and a plurality of out of phase output signal; And operation control unit so that make the cyclical variation device output signal be set in each measurement mutually the time change, and the driving of drive circuit is changed mutually.Like this, drive phase, can change by phase change time corresponding to receive and detect sequential with drive signal by changing.Like this, when ultrasound wave was received, the noise synchronous with survey frequency or hyperacoustic transmission frequency can not occur mutually same, but disperseed.Therefore, can reduce measuring error.

The synchronizing signal that frequency variation apparatus output obtains by signal and the stack of second frequency signal with first frequency, wherein first frequency is hyperacoustic operating frequency, and second frequency is different with first frequency; Control module is by drive circuit output signal of output when measuring at every turn, and wherein the second frequency of cyclical variation device is changed at this.Like this, the periodicity of flow-rate measurement can be disturbed.As a result, when ultrasound wave was received, the noise synchronous with survey frequency or hyperacoustic transmission frequency can not occur mutually same, but disperseed.Therefore, can reduce measuring error.

Cyclical variation device switch has the situation of second frequency and does not have setting between the situation of second frequency.Like this, detect sequential owing to changed reception, so the periodicity of flow-rate measurement can be disturbed by the vibration that changes the hyperacoustic ultrasonic converter of transmission.As a result, when ultrasound wave was received, the noise synchronous with survey frequency or hyperacoustic transmission frequency can not occur mutually same, but disperseed.Therefore, can reduce measuring error.

The cyclical variation device changes the phase place setting of second frequency.Like this, detect sequential owing to changed reception, so the periodicity of flow-rate measurement can be disturbed by the vibration that changes the hyperacoustic ultrasonic converter of transmission.As a result, when ultrasound wave was received, the noise synchronous with survey frequency or hyperacoustic transmission frequency can not occur mutually same, but by dispersion/homogenizing.Therefore, can reduce measuring error.

The cyclical variation device changes the frequency configuration of second frequency.Like this, detect sequential owing to changed reception, so the periodicity of flow-rate measurement can be disturbed by the vibration that changes the hyperacoustic ultrasonic converter of transmission.As a result, when ultrasound wave was received, the noise synchronous with survey frequency or hyperacoustic transmission frequency can not occur mutually same, but disperseed.Therefore, can reduce measuring error.

The cyclical variation device comprises the delay cell that can be set different time delays; And control module is when hyperacoustic each transmission, or each receive to change when detecting postpone to be provided with.Like this, in a measurement procedure, ultrasound wave reverberation of transmitting in the last measurement that is right after and the hangover of ultrasonic converter influence can be disperseed, and can reduce measuring error whereby.

The periodic width that is changed by the cyclical variation device is several times as much as and travel-time variation (this is caused by measuring error) corresponding value.Like this, be added and during homogenizing, it is minimum that error can be reduced to when the measured value that is used for all settings.

Equal a resonant frequency cycle of ultrasonic converter by the periodic width of cyclical variation device change.Like this, in the value that obtains by the measured value phase adduction homogenizing that will be used for all settings, the measuring error that is caused by the hangover of ultrasonic resonance or ultrasonic converter is reduced to minimum.Therefore, can reduce measuring error.

Used identical of the pattern order that is used for the cycle that changes and the measurement of the measurement of updrift side and downstream direction.Like this, the hyperacoustic measurement with side transmission is upstream always carried out under identical condition with the hyperacoustic measurement with side transmission downstream.As a result, when being arranged on flow rate and changing, also can access reliable measurement result.

Predetermined times is several times as much as the change frequency of cyclical variation device.Like this, all setting values of cyclical variation device all are arranged in the flow-rate measurement operating process equably.As a result, can access reliable measurement result.

Flowmeter of the present invention comprises: the flow-rate measurement unit, treat fluid measured this unit of can flowing through; A pair of ultrasonic converter, this converters are used for the transmission ultrasound wave in the flow-rate measurement unit; Be used to drive the drive circuit of one of ultrasonic converter; The receiving test circuit that links to each other, is used to detect ultrasonic signal with another ultrasonic converter; Be used to measure first timer in the travel-time of ultrasonic signal; Second timer is used to measure and detects reception from receiving test circuit and change this time period up to the value of first timer; The control module that is used for the Control Driver circuit; And the computing unit that is used for calculating flow rate by the output of first timer and second timer; Wherein second timer is proofreaied and correct by first timer.Because utilization cuts the value that obtains by the value with second timer and carries out flow rate calculation from the value of first timer, so the resolution of time measurement equals the resolution of second timer.And, because the running time of second timer is very short, therefore can reduce power consumption.Like this, can access that power consumption is little, high-resolution flowmeter.And, after before carrying out flow-rate measurement, proofreading and correct,, just can obtain correct flow-rate measurement as long as operate second timer with stable manner always.Therefore, even when second timer can not be steady in a long-term, also can carry out stable measurement.Like this, can access the flowmeter of pin-point accuracy with common application parts.

This flowmeter comprises a stability sensor, wherein changes so that when being equal to or greater than setting value when the output of temperature sensor, and second timer is proofreaied and correct by first timer.Like this,, also can proofread and correct second timer, can carry out correct measurement whereby in each time that temperature variation occurs even during the characteristic that changes in the with good grounds variation of temperature of second timing appliance.And, only must the time just carry out such correction, thereby can reduce power consumption.

This flowmeter comprises a voltage sensor that is used for the supply voltage of testing circuit, wherein changes so that when being equal to or greater than setting value when the output of voltage sensor, and second timer is proofreaied and correct by first timer.Like this, even in the variation of the with good grounds supply voltage of second timing appliance and during the characteristic that changes, also can proofread and correct second timer in each time that mains voltage variations occurs, and, needn't periodically proofread and correct, thereby can reduce power consumption.

Flowmeter of the present invention comprises: the flow-rate measurement unit, treat fluid measured this unit of can flowing through; A pair of ultrasonic converter, this converters are used for the transmission ultrasound wave in the flow-rate measurement unit; Be used to drive the drive circuit of one of ultrasonic converter; The receiving test circuit that links to each other, is used to detect ultrasonic signal with another ultrasonic converter; Control module, this unit are used for pre-determined number ground Control Driver circuit, drive ultrasonic converter once more so that respond the output of receiving test circuit; Be used for pre-determined number ground and measure the timer in elapsed time; Be used for calculating the computing unit of flow rate by the output of timer; And be used for the cyclical variation device that order changes the driving method of drive circuit, wherein control module is controlled the variable period stabilising arrangement, so that make frequency always keep constant.This structure has been arranged, even when the travel-time changes, survey frequency is also always constant.Like this, when ultrasound wave was received, the noise synchronous with survey frequency or hyperacoustic transmission frequency always occurred mutually same, and no matter whether the travel-time changes.Therefore, measuring error can keep steady state value.As a result, even when noise has the very long cycle, also can make the flow-rate measurement stabilization.

This control module comprises the periodicity stabilising arrangement that is formed by the delay cell that can be set different time delays; And control module changes the output timing of drive circuit by the switching delay number of times.Owing to make time delay survey frequency keep constant by changing, so survey frequency can be stabilized, and can not influence the driving of ultrasonic converter.

The control module control Driver Circuit is so that make Measuring Time keep constant.Like this, it is constant that survey frequency can keep, and only need simple calculating, the travel-time that need not to calculate each ultrasonic transmission.

Brief description of the drawings

Fig. 1 is the block scheme according to the flowmeter of the embodiment of the invention 1.

Fig. 2 is the sequential chart of operating process of the flowmeter of expression embodiment 1.

Fig. 3 is the different wave figure of operating process that is used to represent the flowmeter of embodiment 1.

Fig. 4 is the process flow diagram of operating process of the flowmeter of expression embodiment 1.

Fig. 5 is the process flow diagram of operating process of the flowmeter of expression embodiment 1.

Fig. 6 is the process flow diagram of expression according to the operating process of the flowmeter of the embodiment of the invention 2.

Fig. 7 is the block scheme of expression according to the operating process of the flowmeter of the embodiment of the invention 3.

Fig. 8 is the process flow diagram of operating process of the flowmeter of expression embodiment 3.

Fig. 9 is another process flow diagram of operating process of the flowmeter of expression embodiment 3.

Figure 10 is the block scheme of expression according to the operating process of the flowmeter of the embodiment of the invention 4.

Figure 11 is the process flow diagram of operating process of the flowmeter of expression embodiment 4.

Figure 12 is the block scheme of expression according to the operating process of the flowmeter of the embodiment of the invention 5;

Figure 13 is the block scheme of expression according to the operating process of the flowmeter of the embodiment of the invention 6.

Figure 14 is the structural drawing of the flowmeter of embodiment 6.

Figure 15 is the sequential chart of operating process of the flowmeter of expression embodiment 6.

Figure 16 is another sequential chart of operating process of the flowmeter of expression embodiment 6.

Figure 17 is the process flow diagram of operating process of the flowmeter of expression embodiment 6.

Figure 18 is another process flow diagram of operating process of the flowmeter of expression embodiment 6.

Figure 19 is the opposing party's block diagram of the flowmeter of embodiment 6.

Figure 20 is the sequential chart of expression according to the operating process of the flowmeter of the embodiment of the invention 7.

Figure 21 is the process flow diagram of expression according to the operating process of the flowmeter of embodiment 7.

Figure 22 is the sequential chart of expression according to the operating process of the flowmeter of the embodiment of the invention 8.

Figure 23 is the process flow diagram of expression according to the operating process of the flowmeter of embodiment 8.

Figure 24 is the block scheme of expression according to the operating process of the flowmeter of the embodiment of the invention 9.

Figure 25 is the sequential chart of expression according to the operating process of the flowmeter of embodiment 9.

Figure 26 is the block scheme of expression according to the operating process of the flowmeter of the embodiment of the invention 10.

Figure 27 is the process flow diagram of expression according to the operating process of the flowmeter of embodiment 10.

Figure 28 is the sequential chart of expression according to the operating process of the flowmeter of the embodiment of the invention 11.

Figure 29 is the sequential chart of expression according to the operating process of the flowmeter of the embodiment of the invention 12.

Figure 30 is the sequential chart of operating process of the flowmeter of expression embodiment 12.

Figure 31 is another sequential chart of operating process of the flowmeter of expression embodiment 12.

Figure 32 is the sequential chart of expression according to the operating process of the flowmeter of the embodiment of the invention 13.

Figure 33 is the sequential chart of expression according to the operating process of the flowmeter of the embodiment of the invention 14.

Figure 34 is the process flow diagram of operating process of the flowmeter of the expression embodiment of the invention 15.

Figure 35 is the process flow diagram of operating process of the flowmeter of the expression embodiment of the invention 16.

Figure 36 is the process flow diagram of operating process of the flowmeter of the expression embodiment of the invention 17.

Figure 37 is the process flow diagram of operating process of the flowmeter of the expression embodiment of the invention 18.

Figure 38 is the process flow diagram of operating process of the flowmeter of the expression embodiment of the invention 19.

Figure 39 is the process flow diagram of operating process of the flowmeter of the expression embodiment of the invention 20.

Figure 40 is the process flow diagram of operating process of the flowmeter of the expression embodiment of the invention 21.

Figure 41 is the block scheme of expression according to the operating process of the flowmeter of the embodiment of the invention 22.

Figure 42 is the block scheme of expression according to the operating process of the flowmeter of the embodiment of the invention 23.

Figure 43 is the process flow diagram of expression according to the operating process of the flowmeter of embodiment 23.

Figure 44 is the process flow diagram that the digital filtering of the flowmeter of expression embodiment 23 is handled.

Figure 45 is the filtering characteristic figure of operating process of the flowmeter of expression embodiment 23.

Figure 46 is the process flow diagram of operating process of the flowmeter of the expression embodiment of the invention 24.

Figure 47 is the process flow diagram of operating process of the flowmeter of the expression embodiment of the invention 25.

Figure 48 is the process flow diagram of operating process of the flowmeter of the expression embodiment of the invention 26.

Figure 49 is the process flow diagram of operating process of the flowmeter of the expression embodiment of the invention 27.

Figure 50 is the process flow diagram of operating process of the flowmeter of the expression embodiment of the invention 28.

Figure 51 is the block scheme of expression according to the flowmeter of the embodiment of the invention 29.

Figure 52 is the block scheme of expression according to the flowmeter of the embodiment of the invention 30.

Figure 53 is the block scheme of cyclical variation device of the flowmeter of embodiment 30.

Figure 54 is the sequential chart that the reception of the flowmeter of expression embodiment 30 detects sequential.

Figure 55 is the block scheme of expression according to the flowmeter of the embodiment of the invention 31.

Figure 56 is the block scheme of cyclical variation device of the flowmeter of embodiment 31.

Figure 57 A is the block scheme of cyclical variation device of the flowmeter of the embodiment of the invention 32.

Figure 57 B is the sequential chart that the reception of the flowmeter of expression embodiment 32 detects sequential.

Figure 58 is the block scheme of cyclical variation device of the flowmeter of the embodiment of the invention 33.

Figure 59 is the block scheme of cyclical variation device of the flowmeter of the embodiment of the invention 34.

Figure 60 is the block scheme of cyclical variation device of the flowmeter of the embodiment of the invention 35.

Figure 61 is the block scheme of expression according to the flowmeter of the embodiment of the invention 36.

Figure 62 is the accompanying drawing of expression according to the operating process of first timer of the embodiment of the invention 36 and second timer.

Figure 63 is the block scheme of expression according to the flowmeter of the embodiment of the invention 37.

Figure 64 is the block scheme of the conventional flowmeter of expression.

Figure 65 is the block scheme of another conventional flowmeter of expression.

Figure 66 is the block scheme of another conventional flowmeter.

Figure 67 is the process flow diagram of the operating process of the another conventional flowmeter of expression.

Figure 68 is the block scheme of expression one conventional flowmeter.

Finish best mode of the present invention

Below, with reference to the accompanying drawings embodiments of the invention are described.

(embodiment 1)

Fig. 1 is the block scheme of expression according to the flowmeter of the embodiment of the invention 1.In Fig. 1, reference number 117 is first transmission, and this device is configured in the stream 116, and by with hyperacoustic transmission as the state variation in the fluid transmission as transmitting/receiving signal.Reference number 118 is second transmission as transmission.Reference number 119 is to be used for carrying out between first transmission 117 and second transmission 118 repeatedly the duplicating device that signal is propagated.Reference number 120 is a time register, hyperacoustic travel-time that its repetitive process that is used for being determined at duplicating device 119 is propagated.Reference number 121 is flow rate detection devices, and it is used for detecting flow rate according to the value from time register 120.Reference number 122 is number of times modifiers, and it is used for changing in succession predetermined multiplicity.In addition, this flowmeter also comprises: elapsed time pick-up unit 123, and it is used for detecting midway (halfway) information relevant with the travel-time of repetitive 119 repetitive propagation; Frequency detecting device 124, it is used for according to the frequency that detects flow rate variation from the information of elapsed time pick-up unit 123; And number of times modifier 122, it is used for change being provided with, so that make minute be essentially the several times of the frequency period that frequency detecting device 124 detected.Here, in the travel-time that stored data keep transmission in the data hold 125, this travel-time is obtained by elapsed time pick-up unit 123.Compare by data that data hold 125 is preserved and the travel-time data of being surveyed, frequency detecting device 124 detects frequency.Reference number 126 is switchgears, and it is used for switching the transmission operation between first transducer 117 and second transducer 118.Reference number 127 is the transmitters that are used to transmit ultrasonic signal.Reference number 128 is the receivers that are used for received ultrasonic signal.

Below, 2-5 describes the operating process and the function of this flowmeter with reference to the accompanying drawings.As shown in Figure 2, in flowmeter of the present invention, respond a repeated priming signal and begin to measure.An input signal is transfused to first transducer, and the vibration of first transducer is with the transmission ultrasound wave.This ultrasound wave is received by second transducer.According to a predetermined clock number, time register is measured the travel-time of transmission signals.Be the stand-by period of fixing the time delay in the accompanying drawing, and it is used to wait for the decay of sound wave.Detecting in the count value with time delay and travel-time is C
iAfter, an input signal is imported in first transducer once more, so that the transmission sound wave, and this sound wave is received by second transducer.This mensuration is repeated pre-determined number.Counting C with the reception of second transducer
I+1With last counting C
iCompare, so that detect the flow rate variation frequency that repeats.For example, as shown in Figure 3, relatively flow rate variation point V5 and V6 count C
5-C
6Between difference be a negative value.Yet relatively flow rate variation point V6 and V7 count C
6-C
7Between difference be one on the occasion of.That is its sign inversion.Then, the difference C between count value
1-C
I+1Once more from negative value become on the occasion of the time, be each replication time according to the process shown in the process flow diagram of Fig. 4, detect frequency whereby.

The flow process of the flowcharting frequency detecting of Fig. 4.Specifically, Fig. 4 represents that keeping a timing counting is in order to compare with next timing counting, to detect the change of flow rate variation whereby.And, as shown in Figure 5, before each flow rate is measured implementation 1. with the number of times modifier.By this way, detect frequency, and in this cycle, repeat the mensuration in travel-time.As a result, the influence that is not changed just can be measured flow rate, even this is because when flow changes, by being to measure in the time interval to make the flow rate equalization of being surveyed with a period of change.When not only in one-period but also in a plurality of cycles, measuring, can carry out flow rate with more reliable mode pin-point accuracy ground and measure.

The method that the sign inversion of utilizing the difference between the count value detects frequency had been described already.Yet, also can be by point that detects the difference maximum or the detection that realizes frequency by the point that detection is counted once more to the most approaching count value of preserving count value.In addition, described utilization already and preserved the detection method that data compare with one.Yet, can also detect frequency by the following method: promptly, utilize the method for the automatically relevant or frequency analysis of a plurality of preservation data by use, or by obtaining the difference between a plurality of preservation data as mentioned above.

Like this, this flowmeter need not to be used to detect the device of fluctuations in discharge, that is, its structure can be simplified.Before carrying out flow rate detection, detect frequency according to the information midway of time register, thereby the time that is used in replication is the several times in a change frequency cycle.Therefore, can carry out flow rate mensuration in more reliable mode pin-point accuracy ground.Data hold is preserved and each timing information constantly relatively, whereby can each the time machine testing frequency.In addition, by changing multiplicity in succession, the influence that can reduce to cause by the change of fluctuations in discharge, the result can carry out reliable flow rate and measure.Moreover, before carrying out flow rate mensuration, multiplicity is set to be the several times in a change frequency cycle.Like this, make the variation of flow average, and its result, can carry out flow rate with reliable mode pin-point accuracy ground and measure.

(embodiment 2)

Fig. 6 is the process flow diagram of expression according to the operating process of the flowmeter of the embodiment of the invention 2.Embodiment 2 is different from embodiment 1, and wherein the process of embodiment 2 is by structuring, makes the frequency that obtains according to frequency detecting device and the multiplicity measured is used to during next flow rate measures.The structure of the flowmeter among the embodiment 2 identical with shown in Fig. 1.

As shown in Figure 6, measure the hyperacoustic travel-time T1 that propagates from first transducer, incite somebody to action the mensuration information C of determinator this moment simultaneously
iBe stored in the data hold.Measure the hyperacoustic travel-time T2 that propagates from second transducer then, and according to time T 1 and T2 calculated flow rate speed and flow rate.Then, utilize the method described in the embodiment 1, according to the timing information C that is preserved
iDetect the frequency of fluctuations in discharge, and change the multiplicity of next time measuring, so that in measuring, reflect the frequency that is detected next time.

By this way, the fluctuations in discharge frequency that is detected can be used for can measuring flow rate and frequency simultaneously whereby in next mensuration.If only for the change detected frequency, then needn't the replication ultrasonic propagation, therefore, can reduce current drain.Can multiplicity be set according to change frequency, thereby make this variation homogenizing, and flow rate is measured on mode pin-point accuracy ground reliably.

(embodiment 3)

Fig. 7 is the block scheme according to the flowmeter of the embodiment of the invention 3.Embodiment 3 is different with embodiment 1, and wherein the flowmeter of embodiment 3 comprises: flow rate variation recognition device 129 is used to measure the amplitude by the flow rate variation of flow rate detection device 121 detections; And number of times modifier 122, be used to change multiplicity, make the flow rate variation of discerning by flow rate variation recognition device 129 reduce, and make flow rate variation recognition device 129 utilize the standard deviation of flow rate to operate.

Shown in the process flow diagram of Fig. 8, at first measure flow rate Qi.When this flow rate is equal to or greater than predetermined value Qm (for example 100 liters/hour), multiplicity remains unchanged.When this flow rate is lower than predetermined value Qm, obtain standard deviation Hi according to n the data (n pieces of data) before the flow measurement rate Qi of institute.When standard deviation Hi is equal to or greater than predetermined value Hm (for example 1 liter/hour), change multiplicity.At this moment, begin to change (increase) multiplicity with a predetermined value dK (for example twice) from initial value K0.When multiplicity is equal to or greater than pre-determined number Km, again multiplicity is set to initial value and changes since first value again.

By this way, have only when institute's flow measurement rate is lower than predetermined flow rate, just change multiplicity, when flow rate is higher, stop this process whereby, thereby reduced power consumption.When standard deviation is equal to or greater than predetermined value, change multiplicity, so that flow rate variation is diminished, thereby, also can carry out flow rate and measure with reliable mode pin-point accuracy ground even when flow changes.By utilizing standard deviation to discern flow rate variation, can correctly detect variation.And, change multiplicity gradually in the mode that increases progressively, can determine necessary multiplicity whereby, this is because can check this repetition number by few time.

As shown in Figure 9, have only when measuring flow rate to be equal to or less than predetermined flow rate, and standard deviation just operates the multiplicity modifier when being equal to or higher than predetermined value,, in view of the above, can reduce power consumption so that further the number of times of the operation of change number of times is carried out in restriction.

In said method, change number of times in the mode that increases progressively gradually.Yet,, can change number of times degressively if standard deviation increases when number of times changes.In this case, when control the direction that number of times changes according to the variation of standard deviation, when promptly increasing or subtracting, can measure in more reliable mode.In addition, when during as the power supply of flowmeter, reducing power consumption with battery, in view of the above, use traffic meter for a long time.

(embodiment 4)

Figure 10 is the block scheme according to the flowmeter of the embodiment of the invention 4.Embodiment 4 is different from embodiment 1, and wherein the flowmeter of embodiment 4 comprises unusual recognition device 130 and flow rate management devices 131.In the operating process of carrying out as the unusual recognition device 130 of prior defined procedure, and in the operating process of carrying out flow rate management devices 131 the number of operations modifier.

In the process flow diagram as shown in figure 11, in the operating process of execute exception recognition device 130, and in the operating process of carrying out flow rate management devices 131, change multiplicity.Have only when must the time just change multiplicity, thereby can reduce power consumption.That is to say, consider the emergency of execute exception identification, should measure flow rate at short notice.In the flow rate assay method of carrying out according to fluctuations in discharge, unusual identification is slower.When before carry out measuring, changing multiplicity, can be implemented in the short time and measure according to change frequency.And, use any load in order to manage the downstream, and carry out the flow rate management.It is necessary detecting and discern flow rate at short notice.Be similar to unusual identification, before measuring, change multiplicity in order to meet change frequency, can realize at short notice whereby measuring.

(embodiment 5)

Figure 12 is the block scheme according to the flowmeter of the embodiment of the invention 5.Embodiment 5 is different from embodiment 1, and wherein transmission utilizes calorie spread to come the variation of test fluid state.The well heater that reference number 132 representatives are used to generate heat, and reference number 133 representatives are used to receive the temperature sensor of heat.

Also be all to utilize under the situation of heat, can come the change detected frequency according to the variation of calorie spread time at transmitting device and receiving trap, therefore can simplified structure.And, can change the number of times that carries out replication.When the replication number of times was the several times in a change frequency cycle, mode pin-point accuracy ground carried out flow rate mensuration reliably.In addition, change the number of times that repeats in succession, and reduce the influence that changes rapidly, measure thereby can carry out flow rate in reliable mode according to the change of fluctuations in discharge.Moreover, carry out before flow rate measures, immediately multiplicity is arranged to the several times in a change frequency cycle, in view of the above, the variation of flow is by homogenizing, thus mode pin-point accuracy ground carries out the mensuration of flow rate reliably.

(embodiment 6)

Figure 13 is the block scheme according to the flowmeter of the embodiment of the invention 6.In Figure 13, reference number 223 is represented first piezoelectric sender, and it is to be arranged in stream 224 and to utilize the ultrasound wave that changes as fluid state to carry out first vibrating device of the transmission of transmission.Reference number 225 is represented second piezoelectric sender, and it is second vibrating device that transmission is carried out the transmission of ultrasonic transmission/reception.Reference number 226 is represented a switch (switching device shifter), and it is used to switch the transmission operation of first piezoelectric sender and second piezoelectric sender.Reference number 227 is represented time register, and it utilizes sound to measure ultrasound wave repeats transmission between first piezoelectric sender 223 and second piezoelectric sender 225 travel-time around method.Reference number 228 is represented the flow rate detection device, and it detects flow rate according to the value that time register records.Reference number 229 is represented change detecting device, and it changes by the pressure that utilizes first piezoelectric sender 223 and second piezoelectric sender 225 to measure in the stream.Control device are measured in reference number 230 representative, and it is used to be synchronized with change detecting device and detects the moment that pressure changes and begin to measure.

Measure control device 230 and carry out mensuration control,, and begin to measure the second minute T2 at the output signal negative edge of change detecting device 229 so that begin to measure the first minute T1 at the output signal rising edge of change detecting device 229.Measure control device 230 execution mensuration and begin control, so that measure for next, carry out the mensuration of the first minute T1 at the output signal negative edge of change detecting device, and begin the mensuration of the second minute T2 at the output signal rising edge of change detecting device.Flow rate determinator 228 is when alternately changing the mensuration beginning, calculate flow rate by consecutive mean first flow rate and second flow rate, wherein first flow rate is utilized the preceding the first minute T1 and the second minute T2 and is obtained, second flow rate utilize after the first minute T1 and the second minute T2 obtain.Reference number 231 representative is as the selector switch of selecting arrangement, and it is used for utilizing the ultrasonic transmission of second piezoelectric sender/receptions operation and pressure change-detection to switch between operating.The hyperacoustic transmitter of reference number 232 representatives.Reference number 233 is represented the ultrasonic reception device.Reference number 234 representatives are used to carry out sound around the duplicating device of measuring.Reference number 235 is represented the operation inspection device, and it is used to check the operation of first piezoelectric sender and second piezoelectric sender.

Below, the operation and the function of flowmeter are described with reference to Figure 14-19.In having the stream of structure shown in Figure 14, ultrasound wave is T1=L/ (C+Vcos θ) from the travel-time T1 of first piezoelectric sender, 223 to second piezoelectric senders 225.Ultrasound wave is T2=L/ (C-Vcos θ) from the travel-time T2 of second piezoelectric sender, 225 to first piezoelectric senders 223.Here, V represents the fluid velocity in the stream, and C represents the velocity of sound, and θ represents the angle of inclination.Utilize inverse poor of T1 and T2, obtain flow velocity degree V by T1 and T2, referring to following formula:

1/T1-1/T2＝2Vcosθ/L

V＝(L/2cosθ)·(1/T1-1/T2)

Change if having pressure in the stream, then change and change the flow velocity degree according to pressure.Like this, following expression T1 and T2:

T1＝L/(C+Vcosθ+u·sin(2πft))

T2＝L/(C-Vcosθ-u·sin(2πft+ψ))

Wherein f represents change frequency, and u represents the variation flow rate degree, and ψ represents the difference (differing) of the initial time and the initial time that T2 measures of T1 mensuration.The inverse of following expression T1 and T2 is poor:

That is, when having variation, can measure flow velocity degree V, and the mensuration of flow rate can be considered the sectional area of stream.In above example, the mensuration according to a transmission operation has been described.Yet, utilize sound around method obtain shown in following formula, can similarly to represent T1 and T2 in the situation of cumulative time (wherein utilizing the 234 replication travel-times of duplicating device):

T1＝∑[L/(C+Vcosθ+u·sin(2πfti))]

＝∑L/(∑(C+Vcosθ)+∑(u·sin(2πfti)))

T2＝∑[L/(C-Vcosθ-u·sin(2πfti+ψ))]

＝∑L/(∑(C+Vcosθ)+∑(u·sin(2πfti+ψ)))

Wherein, the i representative voice around number of times, and ∑ representative is from the integration of i=1 to N.Sound is a kind of method that repeats hyperacoustic transmission around method, obtains long total travel-time whereby, has therefore increased the accuracy of measuring.Here, omitted the detailed mensuration process of sound around method.

That is, when having variation, can measure flow velocity degree V, and the mensuration of flow rate can be considered the sectional area of stream.

When the mistiming, ψ was π, describe to pick up counting with reference to Figure 15.By the alternately zero crossing of component that compares with comparer and detected pressures changes, can obtain the output signal of change detecting device 229.That is, begin the mensuration of T1 at the rising edge of the output signal of change detecting device, and at sound around pre-determined number measure cumulative time T1.On the other hand, begin the mensuration of T2 at the negative edge of the output signal of change detecting device 229, and at sound around identical pre-determined number measure cumulative time T2.As shown in figure 15, at A, B and the C area test T1 of pressure waveform.At F, G and H area test T2, the amplitude in amplitude that these are regional and A, B and C zone is anti-phase.Like this, can eliminate the variation of pressure.

When changing, pressure just showing-when bearing (peak-peak) balancing waveform (as shown in figure 15), can offset this variation by single measurement operation to each T1 and T2.Yet, just showing when pressure changes-when bearing (peak-peak) asymmetric waveform (as shown in figure 16), can measure the time that begins by appropriate change and offset this variation.That is, begin the mensuration of T1, and measure the cumulative time T1 of predetermined sound around number of times at the rising edge of the output signal of change detecting device 229.On the other hand, begin the mensuration of T2 at the negative edge of the output signal of change detecting device 229, and measure sound around the cumulative time T2 of identical pre-determined number.Then, in next mensuration in the cycle, begin the mensuration of T1 at the negative edge of the output signal of change detecting device, and be sound around pre-determined number measure cumulative time T1.On the other hand, begin the mensuration of T2 at the rising edge of the output signal of change detecting device 229, and be sound around identical pre-determined number measure cumulative time T2.With reference to Figure 16, in the cycle, measure T1 in first mensuration at A, B and C district, measure T2 at F, G and H district.After cycle, (F) quilt is as error, and this is because C is different with the waveform in F district for the poor C-of the institute's measured value between C and F district in first mensuration.In cycle, in the H with phase anti-waveform, I and J district, measure T1 in second mensuration, in K, L and M district, measure T2.In second mensuration after the cycle, the difference of the institute's measured value between J and M district is also by as error, and this is because J is different with the waveform in M district., the ultrasound wave that upstream (upstream) the side transmission from the M district comes is measured, and the ultrasound wave that downstream (downstream) the side transmission from the J district comes is also measured in the cycle in second mensuration.Like this, the signal of institute's measured value has been reversed.As a result, the institute's measured value between J and M district is poor (J-M) by as error.So, if consider C=M and F=J, then when C-(F) and (J-M) adduction mean time mutually, operating result are zero.That is, the pressure variation has been offseted.Obviously, when alternately changing hyperacoustic transmission direction in each mensuration, available constant sequential begins to measure.In above example, two mensuration of measuring the cycle had been described already.Yet, during the asymmetric and more complicated of the waveform that changes when pressure, when the periodicity according to waveform continuously changes the time that begins to measure, repeat to measure, make the measured value homogenizing whereby, in view of the above, error can be reduced to minimum value.

Below, the flow process of measuring with reference to the flow chart description of Figure 17 and 18.At first step, whether the signal of measuring change detecting device is at rising edge.When not detecting rising edge, replication is till the rising edge of the output signal that reaches change detecting device 229.If rising edge does not still appear later in predetermined period of time, then utilize and detect the detection that cancellation element interrupts rising edge.Then, carry out the mensuration of the first minute T1 and the second minute T2.When detecting rising edge, measure the first minute T1.Then, determine that whether the signal of change detecting device 229 is at negative edge.When detecting negative edge, carry out the mensuration of the second minute T2.If still do not occur negative edge after the predetermined time cycle, then utilize and detect the detection that cancellation element interrupts negative edge, and determine not have pressure to change.Then, carry out the mensuration of the second minute T2.According to the first minute T1 and the second minute T2, calculate flow rate Q (j).

In cycle, as shown in figure 18, detect the beginning processing procedure in next mensuration with negative edge.Carry out negative edge and detect after the step, measure the first minute T1.After this, after carrying out rising edge detection step, measure the second minute T2.According to the first minute T1 and the second minute T2, calculate flow rate Q (j+1).When changing the mensuration start time, replication, and mensuration and the consecutive mean first flow rate Q (j) and the second flow rate Q (j+1) calculate flow rate Q whereby.Like this, measured value is by homogenizing, thereby eliminated error in principle.

Because the pressure that utilizes second piezoelectric sender 225 can measure in the stream changes, and therefore need provide a pressure transducer.Like this, the size of flowmeter can be reduced, and the structure of stream can be simplified.In addition, even when pressure changes, also can be with the instant flow rate of measuring in reliable mode pin-point accuracy ground.When the change of pressure variation is reversed, carry out and measure, the phase place of pressure variation and mensuration timing can translation whereby.Like this, can be offset owing to pressure changes the error at measurment that causes.And in each mensuration, the timing of measuring is in alternate on schedule and between the negative point, thereby even when asymmetric, also can be offset the influence of pressure variation when pressure changes between high-pressure side and low-pressure side.And, repeat to measure around method according to sound, whereby in single mensuration average measurement value in the cycle.Therefore, can carry out flow rate in reliable mode measures.In addition, utilize selecting arrangement, can select at least one device in first and second vibrating devices and be used for pressure detection.Like this, can realize flow rate mensuration and piezometry.Be changed near zero some place change detected at pressure, can correctly grasp change frequency whereby, and can be offset flow rate.Even when not changing, also can measure flow rate at the fixed time automatically.Piezoelectric sender uses with vibration detection device.Therefore, ultrasound wave also can be used for detected pressures and changes when being used for transmission.And, need not to guarantee a place that is used to install the pressure-detecting device that is exclusively used in pressure detection, and can reduce to cause the part count of escape of liquid.

It should be noted, even when the pressure-detecting device that is exclusively used in pressure detection in utilization carries out the pressure change-detection (having described this detection in this embodiment), also can obtain the identical functions effect.The example that second piezoelectric sender that is positioned at the downstream is used to pressure detection had been described.Yet, even when first piezoelectric sender that is configured in upstream side is used for pressure detection, also can access identical effect.And, even as shown in figure 19, when second piezoelectric sender in first piezoelectric sender of upstream side and downstream alternately is used for pressure detection, also can access identical effect.In addition, by being used alternatingly piezoelectric sender, can check the mode of operation of each piezoelectric sender.That is, when change detecting device detects same signal frequency from these two piezoelectric senders, can determine that these two piezoelectric senders are in operate as normal.

In above-mentioned example, this flowmeter is the determinator for general objects.Yet when flowmeter of the present invention was used in the gasometer, this flowmeter can be configured in the pipeline that fluctuation occurs, for example used the piping system of steam turbine heat pump.And, changed and described this embodiment in conjunction with pressure.Yet,, also can obtain identical effect obviously for flow rate variation.

(embodiment 7)

Figure 20 is the sequential chart of expression according to the operating process of the flowmeter of the embodiment of the invention 7.Embodiment 7 is different from embodiment 6, and wherein the flowmeter of embodiment 7 comprises duplicating device 234, and it is used for repeatedly carrying out around method according to sound the transmission of signal in the time period that is several times as much as a change frequency cycle.The structure of the flowmeter of embodiment 7 as shown in figure 13.

In example shown in Figure 21, be that the interval begins to measure with predetermined amount of time (for example 2 seconds).When reaching the schedule time, utilize change detecting device 229 to measure and the change detected frequency.Then, the number of times of sound around process is set, so that meet change frequency basically.For example, by using the velocity of sound, can calculate one and propagate the time that is spent, wherein piezoelectric sender transmission ultrasound wave divided by the distance between the piezoelectric sender.The time that the once propagation that calculates by using is spent can be calculated the number of times of required sound around process divided by the frequency of being surveyed.Repeat the mensuration of flow rate on around the basis of the number of times of process at sound.In the step of Figure 21 7., the process of carrying out Figure 17 7..

By this way, change the number of times of sound,, can measure the one-period of change frequency whereby so that meet change frequency around process.Therefore, pressure changes by homogenizing, and mode is measured flow rate reliably.Carry out this mensuration and sound and conform to around the process cycle with the sound of several times around the number of times of process when pressure is synchronous, mode be carried out flow rate and measured more reliably whereby.And, owing to utilize the signal of piezoelectric sender can detected pressures synchronous, therefore can access synchronous effect, that is, and can the change detected frequency, and carry out flow rate in reliable mode and measure.

In Figure 20, the mensuration to two cycles has been described.Yet, when propagation distance more in short-term, in order to increase the accuracy of mensuration, the sound that need carry out Duoing than pre-determined number is around (sing-around) process.Therefore, during less than pre-determined number, determine the number of times of sound, around the process number of times when the sound that obtains from change frequency so that it is several times as much as change frequency around process.

(embodiment 8)

Figure 22 is the sequential chart of expression according to the operating process of the flowmeter of the embodiment of the invention 8.Embodiment 8 is different from embodiment 6, wherein the flowmeter of embodiment 8 comprises duplicating device 234, it is used to hyperacoustic mensuration of being transmitted/receiving, when carrying out predetermined variation (for example when output signal descends) with the output of convenient change detecting device 229, begin to be transmitted/hyperacoustic mensuration of receiving, lay equal stress on multiplexed voice around process, when predetermined variation is carried out in the output of change detecting device (for example when output signal descends).The flowmeter of embodiment 8 has structure shown in Figure 13.

As shown in figure 23, the rising edge of change detected detection signal when measuring beginning, and beginning sound is around process.Then, when change detection signal rises once more, stop sound, and measure the first minute T1 around process.Then, the negative edge of change detected detection signal when measuring beginning, and beginning sound is around process.Then, when change detection signal descends once more, stop sound, and measure the second minute T2 around process.According to minute T1 and T2, calculate flow rate.

By this way, the beginning of mensuration and the frequency that stops all changing with pressure are consistent, and therefore, can measure according to change frequency.Like this, pressure changes by average, and measures flow rate in reliable mode.

(embodiment 9)

Figure 24 represents is structure according to the flowmeter of the embodiment of the invention 9.Embodiment 9 is different from embodiment 6, and wherein the flowmeter of embodiment 9 comprises: two counting assemblys 236, and it is used for the variation of output signals of change detecting device 229 is counted; And flow rate detection device 228, in this device, measure, so that the count value that makes counting assembly 236 the very first time measure and second timing between different, and have only when all combinations of two all reach identical number of times, just carry out flow rate mensuration.The sequential chart of this mensuration as shown in figure 25.

As shown in figure 25, when with two cycles being unit when repeating to change, for example, the output signal that is output as (1,0) and change detecting device at counting assembly begins the mensuration of T1 when being positioned at rising edge.Begin the mensuration of T2 at the follow-up negative edge of change detecting device.This be determined at can be expressed as in theory Q (i)=(A-B+C)-(B+C-D)=A+D.In next mensuration in the cycle, the output signal that is output as (1,1) and change detecting device at counting assembly begins the mensuration of T1 when being in negative edge.Begin the mensuration of T2 at the follow-up rising edge of change detecting device.This being determined in theory can be expressed as: Q (i+1)=(B+C-D)-(C-D+A)=-A-B.Follow-up being determined in theory can be expressed as: Q (i+2)=(C-D+A)-(D+A-B)=C+B; And Q (i+3)=(D+A-B)-(A-B+C)=-C-D.Like this, Q (i)+Q (i+1)+Q (i+2)+Q (i+3)=0.That is, the variation of pressure has been eliminated.

In above-mentioned example, four mensuration of measuring the cycle have been described.Yet, when the waveform that changes when pressure is asymmetric and complicated, when the periodicity of foundation waveform continuously changes the time that begins to measure, repeating to measure, homogenizing institute measured value whereby is to reduce to minimum value with error.Owing to can carry out mensuration constantly in all changes, thereby realize the equalization of institute's measured value, and mode is measured flow rate reliably.

(embodiment 10)

Figure 26 represents is structure according to the flowmeter of the embodiment of the invention 10.Embodiment 10 is different from embodiment 6, and wherein the flowmeter of embodiment 10 comprises: frequency detecting device 237, and it is used for the signal frequency of change detected pick-up unit 229; And measure control device 230, it only is used for just beginning mensuration when the frequency that is detected by frequency detecting device 237 equals preset frequency.

As shown in figure 27, have only when the signal of change detecting device 229 equals preset frequency Tm, just begin to measure.Utilize this structure,, also can measure in the predetermined variation frequency even when frequency changes.Even utilize waveform shown in Figure 25,, just can only, specified pressure measure flow rate for changing as long as detect frequency.Like this, even at the pressure change frequency not simultaneously, also mode is measured flow rate at short notice reliably.With a time interval (for example 2 milliseconds) detection flow rate, make whereby to measure and give elasticity, thereby need not to interrupt, can METHOD FOR CONTINUOUS DETERMINATION.

(embodiment 11)

Figure 28 represents is structure according to the flowmeter of the embodiment of the invention 11.Embodiment 11 is different from embodiment 6, and its transmission utilizes heat propagation to come the state variation of test fluid.The well heater that reference number 238 representatives are used to generate heat, reference number 239 representatives are used to receive first temperature sensor of heat, and reference number 240 representatives are used to receive second temperature sensor of heat.Second temperature sensor, 240 state variation of generating heat and coming test fluid according to the resistance change of self own.

Certainly, second temperature sensor also is used as heat transfer/receiving trap, and state variation that whereby can test fluid is that the variation or the pressure of flow velocity changes.And, synchronously carry out a mensuration of measuring the cycle with detected variation.Therefore, can be with carrying out similar mensuration with the described similar reliable fashion pin-point accuracy of former embodiment ground.

(embodiment 12)

Figure 29 is the block scheme according to the flowmeter of the embodiment of the invention 12.In Figure 29, reference number 323 is represented first piezoelectric sender, and it is to be configured in the stream 324 and to utilize ultrasound wave change to carry out first vibrating device of the transmission of transmission as fluid state.Reference number 325 is represented second piezoelectric sender, and it is second vibrating device of carrying out the transmission of hyperacoustic transmission.Reference number 326 is represented a switch (switching device shifter), and it is used to switch the transmission operation of first piezoelectric sender and second piezoelectric sender.Reference number 327 is represented time register, and it is used to measure ultrasound wave repeats transmission between first piezoelectric sender 323 and second piezoelectric sender 325 travel-time.Reference number 328 is represented the flow rate detection device, and it is used for detecting flow rate according to the value that time register is surveyed.Reference number 329 representative pressure change detectors, the change detecting device that it changes with the pressure that acts in the detection stream 324.Reference number 330 is represented the synchronizing pulse output unit, and it is as the change detecting device that the pressure signal of pressure change detector 329 is converted to digital signal.Reference number 331 is represented and is measured control device, and it is used for controlling measures, so that synchronous constantly with the pressure variation of change detecting device detection.Reference number 332 representatives are used for the transmitter of the transmission of ultrasonic signal.Reference number 333 is represented a receiver as the transmission of ultrasonic signal.Reference number 334 representatives are used to repeat the duplicating device of hyperacoustic transmission.Reference number 335 representatives are used to monitor the unusual mensuration monitoring device of mensuration control device.

Below, the operation and the function of flowmeter are described with reference to Figure 14,30 and 31.In having the stream of structure shown in Figure 14, ultrasound wave is T1=L/ (C+Vcos θ) from the travel-time T1 of first piezoelectric sender, 323 to second piezoelectric senders 325.Ultrasound wave is T2=L/ (C-Vcos θ) from the travel-time T2 of second piezoelectric sender, 325 to first piezoelectric senders 323.Here, V represents the flow velocity degree in the stream, and C represents the velocity of sound, and θ represents the angle of inclination.Utilize the inverse of T1 and T2 poor,, can obtain flow velocity degree V according to T1 and T2 by the above expression formula of conversion, referring to following formula:

V＝(L/2cosθ)·(1/T1-1/T2)

Change if having pressure in the stream, then change and change the flow velocity degree according to pressure.Like this, following expression T1 and T2:

T1＝L/(C+Vcosθ+u·sin(2πft))

T2＝L/(C-Vcosθ-u·sin(2πft+ψ))

The change frequency of f representative pressure wherein, the flow velocity degree that the u representative changes, and ψ represent the difference (differing) of the initial time of initial time that T1 measures and T2 mensuration.The inverse of following expression T1 and T2 is poor:

That is, when having variation, can measure flow velocity degree V, and the mensuration of flow rate can be considered the sectional area of stream.Like this, when ψ=π, the mensuration control device of having measured flow rate when detected pressures changes can be with reliable mode pin-point accuracy ground mensuration flow rate, and the influence of the conversion that is not stressed.In above example, the mensuration according to single transmission operation has been described.Yet, it is evident that, utilizing a kind of method to obtain also can obtaining flow rate similarly in the situation of cumulative time (utilizing the 234 replication travel-times of duplicating device in the method).

As shown in figure 30, when to the schedule time (for example per 2 seconds), enabling signals are measured in 331 outputs of mensuration control device, and wait for that the output signal of synchronizing pulse output unit changes, and the threshold value of this variation is that zero point is passed in the pressure variation.Secondly, when the dropping signal of the output signal of synchronizing pulse output unit 330 is exported as first output signal, begin the mensuration of the first minute T1, and repeat the mensuration in travel-time, till the rising signals of the output signal of synchronizing pulse output unit 330 is as the output of second output signal.In next mensuration in the cycle, when the rising signals of the output signal of synchronizing pulse output unit 330 is exported as first output signal, begin the mensuration of the first minute T1, and repeat the mensuration in travel-time, till the dropping signal of the output signal of synchronizing pulse output unit 330 is as the output of second output signal.Then, utilize flow rate detection device 328 that minute T1 and the T2 that time register 327 obtains is transformed into flow rate, and finish the mensuration of flow rate.

As shown in figure 31, when to the schedule time, measure control device 331 outputs and measure enabling signal.Yet, after predetermined amount of time, when the output signal of synchronizing pulse output unit 330 does not change, measure control device 331 enabling signals of output mensuration automatically, and measure according to predetermined number of iterations (for example 256 times).For example, measuring at interval with 2 seconds and pressure changes in the situation in the 10Hz-20Hz scope, will be set in as the predetermined amount of time of stand-by period in 0.1 second-2 seconds the scope.Yet, in this case, preferably, select 1 second as optimum value.And, predetermined number of iterations is set in 2 times one 512 times the scope.Yet, in this case, preferably, select an optimum value according to the pressure change frequency.

Like this,, also can begin behind the predetermined amount of time to measure, in the time need carrying out flow rate mensuration, can guarantee to carry out the mensuration of flow rate whereby even when after measuring enabling signal output, pressure not occurring and changing.For example, in the flowmeter of gasometer, when taking place, earthquake measures whether air-flow is arranged.Even when earthquake takes place flowmeter wait for pressure change occur, because the pressure variation abnormality can not obtain in the synchronizing pulse output signal, also can carry out flow rate automatically and measure, therefore can overcome any unusual.

In above example, the variation that changes as the pressure in the stream has been described.Yet, it is evident that, even when the flow velocity degree changes, also can utilize flow velocity degree change detecting device to obtain identical effect.

(embodiment 13)

Figure 32 is the sequential chart of expression according to the operating process of the flowmeter of the embodiment of the invention 13.Embodiment 13 is different from embodiment 12, wherein the flowmeter of embodiment 13 comprises mensuration monitoring device 335, when wherein not issuing enabling signal within the section at the fixed time after from the instruction issue of measuring control device 331, before from the next instruction issue of measuring control device, do not measure.The structure of embodiment 13 as shown in figure 29.

Shown in figure 32, when to predetermined minute, measure control device 331 outputs and measure enabling signals.Yet, after such variation of waiting for predetermined amount of time, when the output signal of synchronizing pulse output unit does not change, measure monitoring device 335 and instruct mensuration control device 331 to stop to wait for the variation of synchronization pulse.Measure control device 331 and wait for next minute (for example after 2 seconds).Here, if measuring at interval for 2 seconds, and pressure changes in the scope of 10Hz-20Hz, then can be set in 0.1 second-2 seconds the scope as the predetermined amount of time of stand-by period.Yet, in this case, preferably, select 1 second as optimum value.

As mentioned above, when the pressure variation after measuring the enabling signal issue, not occurring, stop to wait for after the predetermined amount of time passage changing, and do not carry out flow rate mensuration, can avoid the low flow rate of accuracy to measure whereby.In Figure 32, show the time of measuring the first travel-time T1.Yet if synchronizing pulse do not occur when measuring the second travel-time T2, the time of measuring T1 becomes quite long with interval between the time of mensuration T2, and in view of the above, the accuracy of mensuration has reduced.The mensuration that this accuracy reduces can be avoided.And, because measurement operation suspends before next mensuration instruction of issue always, therefore avoided unnecessary mensuration, and can reduce power consumption.For example, by battery-driven gasometer, power consumption has reduced at the microcomputer that is used for controlling security function, in view of the above, can obtain the long life-span.

(embodiment 14)

Figure 33 is the sequential chart of expression according to the operating process of the flowmeter of the embodiment of the invention 14.Embodiment 14 is different from embodiment 12, wherein the flowmeter of embodiment 14 comprises mensuration monitoring device 335, wherein when not issuing end signal in one section predetermined amount of time after the enabling signal issue, can finish ultrasonic reception, and export enabling signal once more.The structure of the flowmeter of embodiment 14 as shown in figure 29.

As shown in figure 33, when to predetermined minute, measure control device 331 outputs and measure enabling signals, and, measure so that begin in the output signal negative edge of synchronizing pulse output unit first output signal in view of the above.Secondly, after one period schedule time, second output signal (negative edge) of the output signal of synchronizing pulse output unit waits for that synchronization pulse finishes when not occurring, and the enabling signal of output mensuration once more.Here, if measuring at interval for 2 seconds, and pressure changes in the scope of 10Hz-20Hz, then can be set in 0.1 second-2 seconds the scope as the predetermined amount of time of stand-by period.Yet, in this case, preferably, select 1 second as optimum value.Selected for 1 second,, also can after 2 seconds, finish mensuration before reaching by next minute even measure (redeterminating) once more.Do not occur second output signal in the process if redeterminate, the arrival of next minute is just waited in operation so.

As mentioned above, when the pressure variation after measuring beginning, not occurring, stop after the predetermined amount of time waiting for changing, and do not carry out flow rate and measure, can avoid inaccurate flow rate mensuration whereby.And, owing to redeterminate, can avoid the shortage of a certain period measurement data, and can successfully carry out for example equalization of mensuration process, can improve the accuracy of the flow rate value of surveying whereby.In addition, about measuring the instruction that finishes, time register can not carried out wrong mensuration, and the accuracy of measuring has descended.Can avoid the low mensuration of this accuracy.And, force to finish to measure, can not stop the mensuration process owing to wait for END instruction whereby.Like this, this process can proceed to back one step.Therefore, mode is carried out measurement operation reliably.

(embodiment 15)

Figure 34 is the process flow diagram of expression according to the operating process of the flowmeter of the embodiment of the invention 15.Embodiment 15 is different from embodiment 12, and wherein the flowmeter of embodiment 15 comprises and measures monitoring device 335, wherein when not issuing end signal within the predetermined amount of time T after the enabling signal issue, and the end ultrasonic reception, and abandon the data surveyed.The structure of the flowmeter of embodiment 15 as shown in figure 29.

As shown in figure 34, after output signal output, when second output signal of representing the one-period end through schedule time T (for example 0.5 second) is not afterwards also issued, finish to repeat hyperacoustic transmission, and the data of measuring before abandoning.Then, after suspending a predetermined amount of time, restart to measure.

As mentioned above, when mensuration does not have to abandon the data of surveying when successful, the data that can only utilize pin-point accuracy to measure whereby, and carry out measurement operation in reliable mode.In addition, need not to store the data of surveying, in view of the above, can reduce the power consumption of mensuration.And, whether long by monitoring schedule time T than one-period mensuration circulation (for example 2 seconds), can measure, so that minute does not overlap each other.Even, also can manage measurement operation by the identical schedule time T of control when owing to temperature variation causes hyperacoustic travel-time not simultaneously.

(embodiment 16)

Figure 35 is the process flow diagram of expression according to the operating process of the flowmeter of the embodiment of the invention 16.Embodiment 16 is different from embodiment 12, and wherein the flowmeter of embodiment 16 comprises mensuration monitoring device 335, wherein when multiplicity is equal to or greater than pre-determined number N1, finishes ultrasonic reception, and abandons the data of surveying.The structure of the flowmeter of embodiment 16 as shown in figure 29.

As shown in figure 35, after the output of first output signal, when if hyperacoustic transmission repeats pre-determined number N1 (for example 512 times) or more times, second output signal that one-period finishes is not represented in issue, finish so to repeat hyperacoustic transmission, and the data of measuring before abandoning.Then, after suspending a predetermined amount of time, restart to measure.

As mentioned above, when mensuration is unsuccessful, abandon the data of surveying, can only utilize the data of pin-point accuracy mensuration whereby, and carry out measurement operation in reliable mode.In addition, need not to store the data of surveying, in view of the above, can reduce the power consumption of mensuration.And, even, also can carry out the mensuration in travel-time by the control multiplicity separately, till the limit of multiplicity when owing to temperature variation causes hyperacoustic travel-time not simultaneously.

(embodiment 17)

Figure 36 is the process flow diagram of expression according to the operating process of the flowmeter of the embodiment of the invention 17.Embodiment 17 is different from embodiment 12, and wherein the flowmeter of embodiment 17 comprises mensuration monitoring device 335, wherein when multiplicity is equal to or less than pre-determined number N2, abandons the data of surveying, and exports enabling signal once more.The structure of the flowmeter of embodiment 17 as shown in figure 29.

As shown in figure 36, in the predetermined mensuration of carrying out according to change frequency, when multiplicity is equal to or less than pre-determined number N2 (for example 100 times), the data of measuring before abandoning.Then, after suspending a predetermined amount of time, restart to measure.

Even when mensuration is correctly carried out,, then may grasp pressure improperly and change if multiplicity is equal to or less than pre-determined number.In this case, abandon resulting data and also measure once more, this may be because of the one-period of measuring that surpassed.Therefore, can carry out measurement operation in reliable mode.In addition, need not to store the data of surveying, in view of the above, can reduce the power consumption of mensuration.

(embodiment 18)

Figure 37 is the process flow diagram of expression according to the operating process of the flowmeter of the embodiment of the invention 18.Embodiment 18 is different from embodiment 12, and wherein the flowmeter of embodiment 18 comprises mensuration monitoring device 335, wherein when multiplicity is equal to or less than pre-determined number N2, abandons the data of surveying, and exports enabling signal once more.When the signal of synchronizing pulse output unit 330 arrives second round and makes mensuration last till the end signal issue, as synchronizing pulse output unit 330 outputs second output signal of change detecting device, thus the indicator signal of issue end second round.The structure of the flowmeter of embodiment 18 as shown in figure 29.

As shown in figure 37, in the predetermined mensuration of carrying out according to change frequency, when multiplicity is equal to or less than pre-determined number N2 (for example 100 times), the data of measuring before abandoning.Then, after suspending a predetermined amount of time, when the signal of synchronizing pulse output unit 330 arrives second round, export second output signal, and restart to measure and last till till the end signal issue of second round.

Even when mensuration is correctly carried out,, then may grasp pressure improperly and change if multiplicity is equal to or less than pre-determined number.In this case, abandon resulting data and also measure once more, this may be because the execution of measuring has surpassed one-period.Therefore, can carry out measurement operation in reliable mode.In addition, surpassed two cycles, therefore improved the accuracy of measuring owing to measuring for a long time owing to redeterminate.

(embodiment 19)

Figure 38 is the process flow diagram of expression according to the operating process of the flowmeter of the embodiment of the invention 19.Embodiment 19 is different from embodiment 12, wherein the flowmeter of embodiment 19 comprises mensuration monitoring device 335, wherein when the difference between the second multiplicity N4 of first multiplicity N3 that measures and mensuration is equal to or greater than pre-determined number, export enabling signal once more, and in the mensuration of first multiplicity, ultrasound wave is that first transmission from a pair of transmission is transferred to second transmission, and in the mensuration of second multiplicity, ultrasound wave is to be transferred to first transmission from second transmission.The structure of the flowmeter of embodiment 19 as shown in figure 29.

As shown in figure 38, in the predetermined mensuration of carrying out according to change frequency, when the difference between the first multiplicity N3 and the second multiplicity N4 is equal to or greater than pre-determined number M (for example 10 times), the data of measuring before abandoning.Then, after suspending a predetermined amount of time, restart to measure.

Even,, then may grasp pressure improperly and change if the difference between the first multiplicity N3 and the second multiplicity N4 is bigger measuring when correctly carrying out, the perhaps frequency shift of pressure variation.If so, measurement result is just incorrect.So, abandon resulting data and also measure once more, whereby, can carry out measurement operation in reliable mode.

(embodiment 20)

Figure 39 is the process flow diagram of expression according to the operating process of the flowmeter of the embodiment of the invention 20.Embodiment 20 is different from embodiment 12, wherein the flowmeter of embodiment 20 comprises duplicating device 334, it is used to set multiplicity, so that the first multiplicity N3 of mensuration is equated with the second multiplicity N4 of mensuration, and in the mensuration of first multiplicity, ultrasound wave is that first transmission from a pair of transmission is transferred to second transmission, and in the mensuration of second multiplicity, ultrasound wave is to be transferred to first transmission from second transmission.The structure of the flowmeter of embodiment 20 as shown in figure 29.

As shown in figure 39, in the predetermined mensuration of carrying out, make to measure and carry out second multiplicity, and this number of times equals first multiplicity according to change frequency.That is, make second mensuration carry out the first multiplicity N3, whereby,, also can measure, and can not cause having bigger difference between actual value and the measured value even when the pressure change frequency sharply changes.

Like this, even when the pressure change frequency sharply changes, also can carry out flow rate and measure.For example, in the situation of gasometer, need to guarantee to carry out the time that flow rate is measured safely.Even when the pressure change frequency sharply changes, also can measure as mentioned above, can determine fast that whereby institute's measured value is whether near predetermined flow rate.

(embodiment 21)

Figure 40 is the process flow diagram of expression according to the operating process of the flowmeter of the embodiment of the invention 21.Embodiment 21 is different from embodiment 12, wherein the flowmeter of embodiment 21 comprises mensuration monitoring device 335, it is used to monitor measurement operation, is pre-determined number C so that will export the time number limiting of enabling signal once more, thus the not output of repeated priming signal for good and all.The structure of the flowmeter of embodiment 21 as shown in figure 29.

As shown in figure 40, when measuring once more after the mensuration failure that changes according to pressure, the number of times C (for example being no more than 2 times) that restriction is measured again avoids the output of repeated priming signal for good and all whereby.As a result, can carry out the mensuration of flow rate in reliable mode.

(embodiment 22)

Figure 41 is the block scheme of expression according to the flowmeter of the embodiment of the invention 22.Embodiment 22 is different from embodiment 12, wherein in embodiment 22, utilizes the variation of calorie spread test fluid state.The well heater that reference number 336 representatives are used to generate heat.Reference number 337 representatives are used to receive the temperature sensor of heat.

Even when the temperature sensor that uses as the heat transfer receiving trap, also can be to carry out the mensuration of flow rate continuously with the similar pin-point accuracy of above-mentioned those embodiment, this is to detect each abnormal conditions because measure monitoring device, and carries out different processing procedures according to the abnormal conditions of being surveyed.

(embodiment 23)

Figure 42 is the block scheme of expression according to the flowmeter of the embodiment of the invention 23.In Figure 42, reference number 415 representatives are used to detect the ultrasonic flow rate pick-up unit of instantaneous flow rate; Reference number 416 representative is used for determining that in the mode of pulse the fluctuation whether flow rate value changes determines device; Reference number 417 is represented the flow rate calculation device, is used for utilizing different devices to calculate flow rate value according to the measurement result of the definite device of fluctuation; And reference number 418 representatives are used for the filter processing that the flow rate value is carried out the digital filtering processing.

Below, the operation and the function of this flowmeter are described with reference to Figure 43-45.As shown in figure 43, in flowmeter of the present invention, when being equal to or greater than predetermined value (for example 1 liter/hour) by the difference between the instantaneous flow rate Q (i) of ultrasonic flow rate detection means measure and the preceding instantaneous flow rate Q (i-1) that once measures, fluctuation determines that device determines to exist a pulse.When having pulse, change the filter factor that is used for Filtering Processing according to pulse height.When not having pulse, do not carry out Filtering Processing, and regard the instantaneous flow rate value as stable flow rate.Here, carry out digital filtering according to flow process shown in Figure 3 and handle and be expressed as for example following formula: D (i)=α D (i-1)+(1-α) Q (i), wherein α represents filter factor, and Q (i) represents i instantaneous flow rate, and the stable flow rate that will obtain after D (i) the expression Filtering Processing.This wave filter has the characteristic of low-pass filter shown in Figure 45.When filter factor approached 1 (being generally 0.999), wave filter only allowed low frequency component to pass through.Like this, filtering can be removed the change value, makes it can not pass through wave filter.When amplitude of variation hour, select filter coefficient alpha 2 (general α 2=0.9), thereby and utilize the response characteristic of the flow rate change that this undemanding filtering characteristic is improved to overcome the variation of flow rate fast.And, when amplitude of variation is big, select filter coefficient alpha 1 (general α 1=0.9999), and utilization and substantial low pass filtering characteristic thereof reduce the variation of flow rate value.

In addition, can obtain pulse component A (i): A (i)=Q (i)-D (i) by following formula, and A (i) can be used as amplitude of variation.

So, when being equal to or greater than predetermined value, pulse height carries out Filtering Processing, can remove change component whereby.Therefore, even when pulse occurs, also can utilize a ultrasonic flow rate determinator to stablize the mensuration of flow rate.In addition, can carry out the calculating that is equal to mutually with homogenization process, come storage data and need not a large amount of storeies by Filtering Processing.And, can be that filter coefficient alpha is freely adjusted filtering characteristic by changing a variable.Like this, can adjust filtering characteristic according to pulse height.And, when pulse occurring, select the sharp cut-off filtering characteristic with the bigger pulse stable state of realization, and only when pulse occurring, can carry out Filtering Processing.In addition, judge, adjust Filtering Processing according to the amplitude of variation of pulse whereby according to the amplitude of variation of pulse.And, owing to adjust filtering characteristic, therefore when changing hour according to amplitude of variation, selection allows relaxation (relaxed) filtering characteristic of change fast according to flow rate variation, and when variation is big, select the sharp cut-off filtering characteristic, so that the flow rate variation that causes owing to pulse can obviously reduce.

In this embodiment, described digital filtering disposal route as shown in figure 44.Yet, utilize other filter processing method also can access identical effect.

In above example, flowmeter is a kind of determinator that is used for general objects.Yet when the flowmeter of this embodiment was used for gasometer, this flowmeter can be configured in the flow channel tube that fluctuation occurs, for example used the piping system of steam turbine heat pump.

(embodiment 24)

Figure 46 is the process flow diagram of expression according to the operating process of the flowmeter of the embodiment of the invention 24.Embodiment 24 is different from embodiment 23, and wherein the flowmeter of embodiment 24 comprises the pulse height pick-up unit, is used for detecting according to two flow rate value the amplitude of variation of pulse, and these two flow rate value have been accepted Filtering Processing when changing filter coefficient alpha.

When use has been passed through the stable flow rate value of Filtering Processing with big filter factor, when causing flow rate variation, pulse reduces the response characteristic of flow rate change.Yet, handle by utilizing two wave filters, flow rate sharply changes when occurring even fluctuate, and utilizing also can this variation of fast processing with the flow rate that goes out than the small flow rate coefficient calculations.

(embodiment 25)

Figure 47 is the process flow diagram of expression according to the operating process of the flowmeter of the embodiment of the invention 25.Embodiment 25 is different from embodiment 23, wherein has only when the flow rate value that is detected by the instantaneous flow rate pick-up unit is low, just carries out Filtering Processing.

As shown in figure 47, when the instantaneous flow rate of measuring by the ultrasonic flow rate determinator during less than predetermined flow rate (120 liters/hour), even when pulse occurring, also can correctly measure stable flow rate.In addition, when being equal to or greater than predetermined flow rate by the instantaneous flow rate of measuring by the ultrasonic flow rate determinator, because the ratio of the flow rate that fluctuation causes mensuration amplitude of variation is less.So, can correctly carry out the mensuration of flow rate, and need not Filtering Processing.And because flow rate is less, Filtering Processing is carried out in the utilization filter coefficient alpha of big (for example α=0.999).

As mentioned above, have only and when flow rate is low, just carry out Filtering Processing.Therefore, when flow rate is high, can handle the variation of flow rate rapidly, and the influence of fluctuations that is caused when making flow rate low reduces obviously.

(embodiment 26)

Figure 48 is the process flow diagram of expression according to the operating process of the flowmeter of the embodiment of the invention 26.Embodiment 26 is different from embodiment 23, and wherein filter processing is adjusted filtering characteristic according to flow rate value.

As shown in figure 48, when the instantaneous flow rate of being measured by the ultrasonic flow rate determinator is equal to or greater than predetermined value (for example 120 liters/hour), select filter coefficient alpha 1 (for example α 1=0.9), and when instantaneous flow rate during less than predetermined value, selection filter coefficient alpha 2 (for example α 2=0.999).When flow rate is low, increase filter coefficient alpha 2, so that main mensuration stablized flow rate.For example, when this flowmeter is used for gasometer, can the correct execution Leak Detection, install and determine and air guide nozzle location (pilot-burner registration).On the other hand, when flow rate is high, reduce filter coefficient alpha 1,, improve response characteristic whereby total flow rate to adjust mensuration rapidly according to flow rate variation.

As mentioned above, adjust filtering characteristic according to flow rate value.When flow rate is low, carry out Filtering Processing and when flow rate is higher, can handle the variation of flow rate rapidly.In addition, when flow rate is low, can significantly reduce the influence of fluctuating.As a result, when flow rate is higher, response characteristic can be improved, and when flow rate is low, fluctuation can be reduced.

(embodiment 27)

Figure 49 is the process flow diagram of expression according to the operating process of the flowmeter of the embodiment of the invention 27.Embodiment 27 is different from embodiment 23, and wherein filter processing is the time interval to adjust filtering characteristic with the flow rate minute of ultrasonic flow rate determinator.

As shown in figure 49, when the ultrasonic flow rate determinator is measured the used time segment length (for example 12 seconds) of flow rate, utilize the filter coefficient alpha 1 (for example α 1=0.9) of a smaller value as Filtering Processing.Measure the used time period of flow rate in short-term when the ultrasonic flow rate determinator, utilize the filter coefficient alpha 2 (for example α 2=0.999) of a higher value as Filtering Processing.

Adjust filtering characteristic according to the time period length that flow rate detection is used.When the minute section in short-term, use the relaxation filtering characteristic, and when the minute segment length, use sharp cut-off filtering characteristic can reduce the variation of filtering characteristic whereby.

(embodiment 28)

Figure 50 is the process flow diagram of expression according to the operating process of the flowmeter of the embodiment of the invention 28.Embodiment 28 is different from embodiment 23, wherein adjusts filtering characteristic so that by the amplitude of variation of stablizing the flow rate value that the flow rate calculation element calculates in preset range.

As shown in figure 50, when stablize flow rate variation value that flow rate computation process obtains and being equal to or greater than predetermined value (for example 1 liter/hour), increase filter coefficient alpha after the Filtering Processing, so that control mensuration, thereby reduce the variation of flow rate.When the changing value of flow rate during, reduce filter coefficient alpha, and under the state that flow rate variation is overcome, carry out Filtering Processing less than predetermined value.

Suitably adjust filtering characteristic,, always flow rate variation is reduced to whereby and is equal to or less than predetermined value so that stablize changing value that the flow rate calculation element obtains afterwards in preset range.

Change the increment of filter factor according to the changing value of flow rate.When vary within wide limits, the increment of filter factor increases.When amplitude of variation hour, the increment of filter factor reduces.Utilize this arrangement, can reduce the variation of flow rate smoothly.

(embodiment 29)

Figure 51 is the block scheme of expression according to the flowmeter of the embodiment of the invention 29.Embodiment 29 is different from embodiment 23, wherein in embodiment 29, uses the flow rate detection device 419 based on heat to replace the instantaneous flow rate pick-up unit.

Shown in Figure 51, even when the flow rate detection device 419 that uses based on heat, if exist pressure to change, the flow rate of being surveyed since the pressure variation change.Yet the method for utilizing embodiment 23-28 to describe can obtain identical effect, and can measure flow rate with reliable mode pin-point accuracy ground.

(embodiment 30)

Figure 52 is the block scheme of expression according to the flowmeter of the embodiment of the invention 30.

The flowmeter of embodiment 30 comprises: treat the flow rate determination unit 500 that fluid measured can pass therethrough; A pair of being configured in the flow rate determination unit 500 and the hyperacoustic ultrasonic converter 501 of transmission and 502; Be used to drive the drive circuit 503 of ultrasonic converter 502; Link to each other with ultrasonic converter 503 and detect the receiving test circuit 504 of ultrasonic signal; Be used to measure the timer 505 in the travel-time of ultrasonic signal; The control module 507 that is used for Control Driver circuit 503; Be used for calculating the computing unit 506 of flow rate according to the output of timer; And the cyclical variation device 508 that is used for changing in proper order the driving method of drive circuit 503.Embodiment 30 is different from those conventional examples, and wherein the flowmeter of embodiment 30 comprises cyclical variation device 508.Figure 53 shows the detailed structure of cyclical variation device 508.Reference number 510 is represented first oscillator, wherein produces the oscillator signal of 500KHz.Reference number 511 is represented second oscillator, wherein produces the oscillator signal of 520KHz.Reference number 5 12 representation switch devices, it is according to the output of control module 507 or select the output of first oscillator 510, perhaps selects the output of second oscillator 511, so that selected output is flowed to drive circuit 503.

At first, control module 507 flows to switchgear 512 with switching signal, thereby selects first oscillator 510.Secondly, 505 start times of timer are measured, and control module 507 is given drive circuit 503 with the transmission start signal conveys simultaneously.Receive the transmission start signal, drive circuit 503 utilizes from the oscillator signal of the 500KHz of switchgear 512 inputs and drives ultrasonic converter 502.After this operation of carrying out is the same with those conventional examples.Then, control module 507 flows to switchgear 512 with switching signal, thereby selects second oscillator 511.Then, the flow rate that is similar to the front is measured, the mensuration of the device 505 that picks up counting, and control module 507 is given drive circuit 503 with the transmission start signal conveys simultaneously.Receive the transmission start signal, drive circuit 503 usefulness drive ultrasonic converter 501 from the oscillator signal of the 520KHz of switchgear 512 inputs.

After this, alternately carry out aforesaid operations continuously, thereby measure flow rate.The reception that Figure 54 shows this mensuration detects sequential.As shown in this Fig, the time that receives 500KHz signal and 520KHz signal temporarily moves.As the curve (A) of Figure 54 with (B), the reception of these two signals detects the temporary transient translation of sequential.Like this, in this embodiment, control module control cycle changeable device so that change the mensuration frequency of flow rate in measuring in succession, makes it not keep constant.As a result, when receiving ultrasound wave, the synchronous noise homophase and being disperseed no longer with measuring frequency or hyperacoustic transmission frequency.Therefore, can reduce error at measurment.

The structure of cyclical variation device makes that switching output has a plurality of output signals of different frequency, and handles control module, makes to be each frequency setting that changes in the cyclical variation device of measuring.Therefore, by changing driving frequency, utilization can change reception detection sequential with the corresponding time of cyclical variation of drive signal.Like this, when receiving ultrasound wave, the synchronous noise homophase and being disperseed no longer with measuring frequency or hyperacoustic transmission frequency.Therefore, can reduce error at measurment.

In embodiment 30, change driving frequency by two oscillators of switch.Yet,, just can obtain identical effect as long as when changing driving frequency, drive ultrasonic converter.Regardless of the structure of number, driving frequency and the switchgear of oscillator, can implement the present invention.

(embodiment 31)

Figure 55 is the block scheme of expression according to the flowmeter of the embodiment of the invention 31.

The flowmeter of embodiment 31 comprises: treat the flow rate determination unit 500 that fluid measured can pass therethrough; A pair of being configured in the flow rate determination unit 500 and the hyperacoustic ultrasonic converter 501 of transmission and 502; Be used to drive the drive circuit 503 of one of ultrasonic converter; Link to each other with another ultrasonic converter and detect ultrasonic reception testing circuit 504; Control module 507 is used for pre-determined number ground Control Driver circuit 503, so that drive circuit 503 responds the output of receiving test circuits 504 and drives ultrasonic converter once more; Be used to measure the timer 505 of pre-determined number operation institute elapsed time; Be used for calculating the computing unit 506 of flow rate according to the output of timer 505; And the cyclical variation device 508 that is used for changing in proper order the driving method of drive circuit 503.

Figure 56 is the block scheme of the detailed structure of indication cycle's property changeable device.

Reference number 513 represents first to postpone, and it produces the output signal of 150 μ s after the input signal that receives from control module 507.Reference number 514 represents second to postpone, and it produces the output signal of 150.5 μ s after the input signal that receives from control module 507.Reference number 515 represents the 3rd to postpone, and it produces the output signal of 151 μ s after the input signal that receives from control module 507.Reference number 516 represents the 4th to postpone, and it produces the output signal of 151.5 μ s after the input signal that receives from control module 507.Reference number 517 representation switch devices, its according to output of control module 507 select first to fourth postpone output in the lump selected output is flowed to drive circuit 503.

Embodiment 31 is different from embodiment 1, wherein control module 507 receives the output of receiving test circuit 504 and drives ultrasonic converter once more, and the number of times that this operation repeats is the several times of 4 (4, postpone to be provided with number), and in repetitive process, receive all decay times of order switching cycle changeable device 508 of ultrasound wave at every turn.

In this structure, control module 507 changes delay setting at every turn when detecting ultrasonic reception.Like this, in a measurement operation, can disperse/the ultrasound wave reverberation of transmission in once measuring before the homogenizing and the influence of ultrasound wave hangover, can reduce error at measurment whereby.

The periodic width that is changed by the cyclical variation device is the equal isodisperse of one 2 μ s, and 2 μ s are position (positional) cycles of the resonant frequency (500KHz) of ultrasonic converter.Like this, in the mean value of all these value of setting sums, can reduce to minimum by the error that ultrasound wave reverberation and ultrasonic sensor hangover (being to be the noise of 2 μ s in the cycle) cause.

In addition, the number of times of replication is the multiple of 4 (4, the variation number of cyclical variation device).Like this, in a flow rate mensuration cycle, utilize the mensuration of each predetermined value of cyclical variation device to be performed identical number of times.As a result, reduce the variation of measurement result, in view of the above, can access reliable measurement result.

And the Butut order (order of pattern) that is used for the cycle that changes is all identical with hyperacoustic mensuration of utilizing side transmission downstream in hyperacoustic mensuration of utilizing side transmission upstream.Specifically, during utilizing hyperacoustic mensuration of transmitting downstream from the upstream, select, then, select first to postpone once more according to first delay, second delay, the 3rd delay and the 4th order that postpones; Repeat this circulation.Carry out and utilize hyperacoustic mensuration of upstream transmitting from the downstream, so that according to these delays of identical select progressively.Utilize this arrangement, always under identical condition, carry out hyperacoustic flow rate mensuration that side transmission was downstream measured and utilized to hyperacoustic flow rate of having utilized side transmission upstream.Especially, even when flow rate changes, also can access reliable measurement result.

In embodiment 31, change time delay by switching four delays.As long as can drive ultrasonic converter by changing driving timing, just can access identical effect.Regardless of the structure of time delay, delay number and switchgear, can both implement the present invention.

In above example, will be inserted in time delay between control module 507 and the drive circuit 503.Yet, when be inserted between receiving test circuit 504 and the control module 507 time delay, also can obtain identical effect.

In above example, the width that postpone to change is 2 μ s, and the change number of times of setting is 4, and the difference between the adjacent setting is 0.5 μ s (it be 2 μ s 1/4th).The present invention is not limited to these values.Each of these values all is the value that the multiple by the mean allocation one-period obtains.

(embodiment 32)

Figure 57 A is the block scheme of expression according to the cyclical variation device of the flowmeter of the embodiment of the invention 32.

Reference number 518 is represented oscillator, and 519 represent phase convertor.The oscillator output frequency is the signal of 500KHz.Phase convertor quickens according to the covert signal from control module 507 or the signal phase of delay generator, and output has being accelerated or the signal of the phase place that postpones.For example, when phase control signal is Hi (height), the output of phase convertor former state output oscillator 518.When phase control signal was Lo (low), phase convertor quickened 180 ° with the output signal of oscillator 518 and also exports the signal that is accelerated.Figure 57 B shows the received signal in these operations and receives and detects sequential.

As shown in this Fig, acceptance point is by 1/2 cycle of translation.That is, the translation time is 1 μ s.

By this way, utilizing a time period to change receive to detect sequential, this time period is to drive phase tranformation and convert the phase change of drive signal to the time and obtain by utilizing.So, when receiving ultrasound wave, the synchronous noise homophase no longer with measuring frequency or hyperacoustic transmission frequency, and disperseed.Therefore, can reduce error at measurment.

In embodiment 32, by between two phase places, switching the phase place that changes drive signal.Yet,, just can obtain identical effect as long as can drive ultrasonic converter by changing the driving phase place.Regardless of the structure of reformed phase place and switching device shifter, can both implement the present invention.

(embodiment 33)

Figure 58 is the block scheme of expression according to the cyclical variation device of the flowmeter of embodiment 33.

First oscillator of reference number 520 representative output 500KHz oscillator signals.500KHz is the resonant frequency of ultrasonic converter.Second oscillator of reference number 52 1 representative output 200KHz oscillator signals.Reference number 522 is represented the ON/OFF circuit, and this circuit is according to determining from the ON/OFF switching signal of control module 507 whether the output of second oscillator is exported to waveform adder unit 523.Waveform adder unit 523 synthesizes the waveforms of input, and synthetic waveform is flowed to drive circuit 503.

When with the frequency drives ultrasonic converter of about 500KHz, can receive the bigger ultrasonic signal of amplitude.When a component of signal with 200KHz drives ultrasonic converter, almost do not receive ultrasonic signal.Yet approximately the oscillator signal of 200KHz adds sometimes and does not join sometimes in the oscillation frequency of about 500KHz.This erratic operation makes received ultrasonic signal frequency generation subtle change.As a result, can change reception and detect sequential.So, when receiving ultrasound wave, the synchronous noise homophase no longer with measuring frequency or hyperacoustic transmission frequency, and disperseed.Therefore, can reduce error at measurment.

(embodiment 34)

Figure 59 is the block scheme of expression according to the cyclical variation device of the flowmeter of embodiment 34.

First oscillator of reference number 520 representative output 500KHz oscillator signals, 500KHz is the resonant frequency of ultrasonic converter.Second oscillator of reference number 521 representative output 200KHz oscillator signals.Reference number 524 is represented the phase tranformation unit, and this unit is according to the output of control module 507, and with 180 ° of the phase transition of the output signal of second oscillator 521, and output has the signal of conversion back phase place.Reference number 523 is represented the waveform adder unit, and this unit is used for the waveform of synthetic input and synthetic waveform is outputed to drive circuit 503.

When with the frequency drives ultrasonic converter of about 500KHz, can receive the bigger ultrasonic signal of amplitude.When a component of signal with 200KHz drives ultrasonic converter, almost do not receive ultrasonic signal.Yet, by according to a sum signal and subtle change only takes place the frequency of the received ultrasonic signal of driven ultrasonic converter, this sum signal be by in will measuring at every turn approximately the phase place of the oscillator signal of 200KHz be transformed after 180 ° with the about oscillation frequency addition of 500KHz and obtain.As a result, can change reception and detect sequential.Like this, when receiving ultrasound wave, the synchronous noise homophase no longer with measuring frequency or hyperacoustic transmission frequency, and disperseed.Therefore, can reduce error at measurment.

(embodiment 35)

Figure 60 is the block scheme of expression according to the cyclical variation device of the flowmeter of embodiment 35.

First oscillator of reference number 525 representative output 500KHz oscillator signals, 500KHz is the resonant frequency of ultrasonic converter.Second oscillator of reference number 526 representative output 200KHz oscillator signals.Reference number 527 is represented frequency conversion unit, and this unit is used for the frequency that conversion will be input to the signal of frequency converter, and output has the signal of frequency after the conversion.Here, frequency conversion unit 527 is 1/2 with the frequency transitions of input signal, i.e. 100KHz.Reference number 523 is represented the waveform adder unit, and the waveform that this unit will be used for after the synthetic waveform of importing also will synthesize outputs to drive circuit 503.

When with the frequency drives ultrasonic converter of about 500KHz, can receive the bigger ultrasonic signal of amplitude.When a component of signal with 200KHz or 100KHz drives ultrasonic converter, almost do not receive ultrasonic signal.Yet, by according to two sum signals and subtle change only takes place the frequency of the received ultrasonic signal of driven ultrasonic converter, these two sum signals are respectively by obtaining with the oscillation frequency addition of about 200KHz and about 500KHz and with the oscillation frequency addition of 100KHz and 500KHz.As a result, can change reception and detect sequential.So, when receiving ultrasound wave, the synchronous noise homophase no longer with measuring frequency or hyperacoustic transmission frequency, and disperseed.Therefore, can reduce error at measurment.

(embodiment 36)

Figure 61 is the block scheme of expression according to the flowmeter of the embodiment of the invention 36.

The flowmeter of embodiment 36 comprises: treat the flow rate determination unit 500 that fluid measured can pass therethrough; A pair of being configured in the flow rate determination unit 500 and the hyperacoustic ultrasonic converter 501 of transmission and 502; Be used to drive the drive circuit 503 of ultrasonic converter 502; Link to each other with ultrasonic converter 501 and detect the receiving test circuit 504 of ultrasonic signal; Be used to measure first timer 527 in the travel-time of ultrasonic signal; Second timer 528, its be used to measure from receiving test circuit 504 receive signal the time be carved into time period till the moment that the value of first timer 527 changes; The control module 530 that is used for Control Driver circuit 503; Be used for calculating the computing unit 506 of flow rate according to the output of first timer 527 and second timer 528; On-off circuit 509, be used to switch in ultrasonic converter 501 and 502 and drive circuit 503 and receiving test circuit 504 between connection; Temperature sensor 531, it is used to measure the temperature of flowmeter and measured temperature is flowed to control module 530; And voltage sensor 532, it is used to measure the power source voltage of supply flow rate quantity calculation.

Control module 530 will be measured enabling signal and flow to driving circuit 503, begin the timing of first timer 527 simultaneously.The input of driving circuit 503 response signals and drive ultrasonic converter 502 is with the emission ultrasound wave.Institute's ultrasonic waves transmitted is imported fluid into and is received by ultrasonic converter 501.Receiving test circuit 504 is exported to first timer 527 and second timer 528 with the ultrasonic signal that is received.First timer 527 receives from the input signal of receiving test circuit 504 mensuration with stand-by time.The output of second timer, 508 reception receiving test circuits 504 stops to stop constantly synchronous timing with the counting of exporting from first timer 527 with the mensuration of start time then.Computing unit 506 receives the timing result of first timer 527 and second timer 528 and calculates flow rate.

Figure 62 represents the time sequential routine of first timer 527 and second timer 528.Shown in Figure 62,, therefore carry out the extra mensuration corresponding with the A unit because first timer 527 changes its state in rising edge of clock signal.Because the mensuration resolution of first timer 527 is the interval B among Figure 62, therefore in each mensuration, just produced the A unit of being counted error at measurment.Utilize second timer 528 to measure extra A unit, and it is deducted from computing unit 506, obtain having high-resolution ultrasonic propagation time whereby, and obtained correct flow rate value.

In addition, control module 530 starts first timer 527, simultaneously enabling signal is exported to second timer 528, thereby is started second timer 528.In the moment that first timer counting finishes, one outputs to second timer 528 with the counting constantly synchronous output signal that finishes from first timer 527, thereby second timer 528 is stopped, at this moment, the value of second timer 528 equals time of being surveyed in a clock time of first timer 527.Handle these times at computing unit 506, obtain a clock time corresponding with second timer 528, and proofread and correct a clock time corresponding with second timer 528, this time is used in the calculating.

When the output of temperature sensor 531 or supply voltage sensor 532 changes, carry out this operation to meet or exceed a setting value.Utilize this arrangement, second timer 528 need not to have the stability of temperature and supply voltage.As a result, can use cheap parts.And, need not to proofread and correct, and power consumption can drop to reduced levels busyly.

Owing to the value of utilizing the value deduct second timer 528 from the value of first timer 527 to obtain is carried out flow rate calculation, so timing resolution equates with second timer 528.In addition, because the running time of second timer 528 is very short, therefore can reduce power consumption.Like this, can access the little high-resolution flowmeter of power consumption.And, as long as operate second timer 528 with stable manner after before carrying out flow rate mensuration, having carried out proofreading and correct, just can carry out correct flow rate and measure.Therefore, even when second timer 528 lacks long-time stability, also can carry out correct mensuration.So, can utilize the parts of common application to obtain the flowmeter of pin-point accuracy.

In addition, provide temperature sensor 531.When the output of temperature sensor 531 changes when meeting or exceeding setting value, utilize first timer 527 to proofread and correct second timer 528.Like this, even when second timer 528 has the characteristic that varies with temperature and change, when each temperature changes, proofread and correct second timer 528, thereby can carry out correct mensuration.In addition, have only and just carry out this correction where necessary, therefore can reduce power consumption.

In addition, provide voltage sensor 532.When the output of voltage sensor 532 changes when meeting or exceeding setting value, utilize first timer 527 to proofread and correct second timer 528.Like this, even when second timer 528 has the characteristic that changes with mains voltage variations, when each supply voltage changes, proofread and correct second timer 528, thereby can carry out correct mensuration.In addition, have only and just carry out this correction where necessary, therefore can reduce power consumption.

In addition, owing to carry out this correction, therefore crystal oscillator is used for a clock of first timer 527, and the CR oscillatory circuit is used for a clock of second timer 528.Utilize the clock of crystal oscillator to work in highly stable mode.Yet in such clock, beginning to become stable to operation from operation need take a long time.In addition, though utilize the CR oscillatory circuit can not guarantee to have long-time stability, utilize the CR oscillatory circuit can easily realize operating rapid change timer stable and that operate in asynchronous mode.Crystal oscillator is used for a clock of first timer 527, and the CR oscillatory circuit is used for a clock of second timer 528, thereby can easily realize having high-resolution stable timer.

In Figure 62 of embodiment 36, after second timer began operation, second timer stopped in the moment of the clock signal decline of first timer.Yet the present invention is not limited to this sequential, and this is because as long as this sequential and first timer are synchronous, just can obtain the correct time by the calculating of carrying out subsequently.

(embodiment 37)

Figure 63 is the block scheme of expression according to the flowmeter of the embodiment of the invention 37.

The flowmeter of embodiment 37 comprises: flow rate determination unit 500; A pair of being configured in the flow rate determination unit 500 and the hyperacoustic ultrasonic converter 501 of transmission and 502; Be used to drive the drive circuit 503 of ultrasonic converter 502; Link to each other with ultrasonic converter 503 and detect the receiving test circuit 504 of ultrasonic signal; Control module 507, this unit is used for by pre-determined number control Driver Circuit 503, drives ultrasonic converter 502 once more so that make the output of driving circuit 503 response receiving test circuits 504; Be used to measure the timer 505 of the operation institute elapsed time that carries out pre-determined number; Be used for calculating the computing unit 506 of flow rate according to the output signal of timer 505; And delay cell 533, this unit is that the steady makeup of frequency that is used to continuously change the driving method of drive circuit 503 is put.

Control module 507 will be measured enabling signal and export to delay cell 533, start the timing of timer 505 simultaneously.After the time delay of setting from the setting signal of control module, delay cell 533 is exported to drive circuit 503 with a signal in basis.Respond the input of this signal, drive circuit 503 drives ultrasonic converter 502 with the emission ultrasound wave.Institute ultrasonic waves transmitted successor's fluid is also received by ultrasonic converter 501.Receiving test circuit 504 outputs to delay cell 533 with the ultrasonic signal that is received, make drive circuit with operate in similar mode of last cycle, and transmit ultrasonic signal once more.Received 507 pairs of this repetitive operation countings of control module, and when count value reached pre-determined number, control module 507 stopped timer 505 from the output signal of receiving test circuit 504.Computing unit 506 receives the timing result of timer 505 and calculates flow rate.

Control module 507 receives the value of timer 505 and sets the time delay of delay cell 533, so that its maintenance is constant.By this way, control module 507 controls are measured, so that it is always constant to measure frequency.Utilize this structure, even when the travel-time changes, it is also always constant to measure frequency.As a result, when how the variation no matter in the travel-time received ultrasound wave, the noise synchronous with measuring frequency or hyperacoustic transmission frequency always kept homophase.Therefore, error at measurment can be remained a constant.In view of the above, even when noise has the very long cycle, also can make flow rate measure stabilization.

Control module 507 control lag unit 533 are so that the minute maintenance is constant.Therefore, need not to calculate the travel-time of each ultrasonic transmission and only simply calculate, just can make and measure frequency and keep constant.

In embodiment 37, make time delay the mensuration frequency keep constant by changing.Yet frequency is constant just can to obtain identical effect as long as measure.Specifically, by using distinct methods, for example also can obtain identical effect by the distance that changes between the ultrasonic converter.

Because when having fluid, the travel-time that ultrasound wave is from upstream to the downstream is different from ultrasound wave from swimming over to the travel-time of upstream down, therefore for the stable frequency of measuring, can set different delays.

In addition, big and can be ignored by the error that periodic noise causes the time, the operation of dwelling period stabilising arrangement can reduce power consumption whereby when flow rate.

In addition,, when changing the setting of measuring frequency stabilizing apparatus, measure flow rate, cause the mensuration frequency of measurement result generation minimum change to be set to target mensuration frequency whereby by measuring frequency change in the starting stage of mensuration.Utilize this arrangement, can access more stable measurement result.

Industrial applicibility

As mentioned above, according to flowmeter of the present invention, can obtain following effect.

In order to address the above problem, flowmeter of the present invention comprises: a pair of transmission/reception apparatus, this device are configured in the stream, utilize the state variation of fluid to carry out transmission/reception; Duplicating device is used for repeating transmission/reception; Time register, the propagation that is used for minute or is repeated by duplicating device; The flow rate detection device is used for detecting flow rate according to the measured value of time register; And the number of times modifier, be used for changing predetermined number of repetition. Number of repetition is changed to best number, in order to reduce the impact of changes in flow rate. Therefore, can carry out reliable flow rate mensuration in pin-point accuracy ground.

This flowmeter comprises a pair of transmission/reception apparatus, and this device utilizes hyperacoustic propagation to change as the state of fluid. Like this, by using ultrasonic transmission/receiving system, even when in fluid, going out present condition and changing, also can carry out hyperacoustic propagation. And, changing to best number by the number of repetition that will change, the reliable flow rate that can obtain high accuracy is measured.

This flowmeter comprises transmission/reception apparatus, and this device utilizes calorie spread to change as the state of fluid. Like this, by using the heat transmission/reception apparatus, even when in fluid, going out present condition and changing, also can carry out the propagation of heat. And, changing to best number by the number of repetition that will change, the reliable flow rate that can obtain high accuracy is measured.

This flowmeter comprises: the elapsed time checkout gear, for detection of the information midway by propagation time of duplicating device replication; Frequency detecting device is used for the frequency by the information detection flow rate variation of elapsed time checkout gear; And the number of times modifier, be used for setting minute, in order to being several times as much as basically by frequency detecting device, it detects the volume frequency. Like this, need not the checkout gear that provides special. Carrying out before the flow rate detection, by the change detected of the information midway frequency of time register, and set minute, in order to make it be several times as much as a frequency period. The reliable flow rate that as a result, can obtain high accuracy is measured.

This flowmeter comprises: data hold is used for preserving at least one or more propagation times that repeat transmission/reception that obtained by the elapsed time checkout gear; And frequency detecting device, be used for comparing to detect frequency by the data that data hold is preserved and the propagation time data of surveying. Each timing information is constantly all stored by data hold and is compared, and can detect frequency whereby.

Number of operations modifier in prior defined procedure. Because number of operations modifier just when carrying out prior defined procedure only, so the processing procedure of number of times modifier is limited to required minimum of a value. So, can obviously reduce power consumption.

Number of operations modifier when each predetermined flow rate is measured. Like this, when each predetermined flow rate is measured, change number of repetition, also can measure flow rate with reliable mode pin-point accuracy ground whereby even in the flow that alters a great deal.

Before flow rate mensuration process, implement the number of times modifier. Owing to carrying out before the flow rate mensuration number of repetition being set to pre-determined number, therefore can carry out flow rate with reliable mode pin-point accuracy ground and measure.

Prior defined procedure comprises: the operation of unusually definite device, and this device is used for being measured by the flow rate of surveying the abnormal conditions of flow rate; And the operation of flow rate management devices volume, this device is used for the use state by the flow rate management flow rate of surveying. Owing to only have when unusually measuring process and flow rate management process, just change number of repetition, the operation that therefore changes number of repetition is limited to required minimum of a value. So, can reduce power consumption.

In measuring, next flow rate uses the number of repetition of the frequency adjustment that is obtained by the flow rate detection device. Measure because this number of repetition is used for next, therefore need not frequency detecting is carried out replication. Like this, can reduce power consumption.

When institute's flow measurement rate during less than predetermined flow rate, operation flow rate changeable device. When being equal to or less than predetermined flow rate, just change number of repetition owing to only have, but when flow rate is high, do not implement this process, therefore can reduce power consumption.

Flowmeter of the present invention comprises: transmission/reception apparatus, this device are configured in the stream, utilize the state variation of fluid to carry out transmission/reception; Be used for measuring the determinator by the propagation time of transmission/reception apparatus transmission/reception; The value that is used for the time-based determinator detects the flow rate detection device of flow rate; Utilize transmission/reception apparatus to measure the change detecting device of the variation in the stream; And the mensuration control device, make the mensuration beginning for the variation timing that is synchronized with change detecting device. Because utilize the variation in the transmission receiving system mensuration stream, therefore need not provides another for detection of the sensor that changes. Like this, can reduce the size of flowmeter, and simplify the structure of stream. And, even when changing, also can measure flow rate with reliable mode pin-point accuracy ground at short notice.

This flowmeter comprises a pair of transmission/reception apparatus of utilizing hyperacoustic propagation to change as fluid state. Like this, utilize the state that ultrasonic transmission/receiving system can test fluid to change. The timing that therefore, can be synchronized with variation begins to measure. As a result, can measure flow rate with reliable mode pin-point accuracy ground.

This flowmeter comprises the transmission/reception apparatus that the propagation that utilizes heat changes as fluid state. Like this, utilize the state that hot transmission/reception apparatus can test fluid to change. The timing that therefore, can be synchronized with variation begins to measure. As a result, can measure flow rate with reliable mode pin-point accuracy ground.

This flowmeter comprises: be configured in the stream, receive hyperacoustic first vibrating device and second vibrating device for transmission; Switching device is used for switch is carried out in the transmission reception operation of first vibrating device and second vibrating device; Change detecting device changes for detection of the pressure in the stream of at least one device in first vibrating device and second vibrating device; Time register is used for measuring the hyperacoustic propagation time that is received by first vibrating device and the transmission of second vibrating device; Measure control device, be used for following situation is carried out Synchronization Control: the first, when the output display of change detecting device goes out predetermined variation, determinator is measured the first minute T1 that propagates to second vibrating device in stream downstream from first vibrating device of stream upstream side, it two is, when the output display of change detecting device went out the variation opposite with predetermined variation, determinator was measured the second minute T2 that propagates to first vibrating device of stream upstream side from second vibrating device in stream downstream; The flow rate detection device is used for utilizing the first minute T1 and the second minute T2 to calculate flow rate. Owing to measure in that time that the variation of pressure variations turns to, so pressure changes mutually and the mensuration timing can be drifted about mutually. As a result, changing the evaluated error that causes by pressure can be offset.

This flowmeter comprises: measure control device, be used for following situation is measured control: the first, when the output display of change detecting device goes out predetermined variation, begin the mensuration of the first minute T1, and when the output display of change detecting device goes out the variation opposite with predetermined variation, begin the mensuration of the second minute T2, it two is, in next is measured, when the output display of change detecting device goes out the variation opposite with predetermined variation, begin the mensuration of the first minute T1, and when the output display of change detecting device goes out predetermined variation, begin the mensuration of the second minute T2; And flow rate calculation device, be used for by make first flow rate and second flow rate in succession equalization calculate flow rate, and first flow rate is by utilizing the first previous Measuring Time T1 and the second previous Measuring Time T2, alternately change simultaneously the startup of measuring and obtain, and second flow rate to be the first Measuring Time T1 by utilizing next and the second Measuring Time T2 of next obtain. Like this, change as mentioned above the timing of measurement, in order to the first Measuring Time T1 and the second Measuring Time T2 are measured. As a result, even change when asymmetric between high-pressure side and low-pressure side when pressure, also can offset the impact that this pressure changes.

This flowmeter comprises for the duplicating device that repeatedly carries out transmission/reception. Like this, can average by increasing the measurement number of times, the result can implement reliable flow-rate measurement.

This flowmeter comprises for the duplicating device that repeatedly carries out transmission/reception in the time period that is several times as much as a period of change. Like this, can make pressure change equalization by measuring according to change frequency. As a result, flow rate that can Measurement sensibility.

This flowmeter comprises duplicating device, be used for when the output display predetermined variation of variable checkout gear, the measurement of beginning transmission/reception, and repeat thisly to have hyperacoustic transmission/reception and measure is until during the variation identical with predetermined variation of the output display of variable checkout gear. Like this, the frequency that pressure changes is all deferred in the beginning of measurement and termination. Therefore, can measure change frequency and make pressure change equalization. As a result, flow rate that can Measurement sensibility.

This flowmeter comprises the selecting arrangement for the following situation of switch: a kind of situation is, first vibrating device and second vibrating device are used for hyperacoustic transmission/reception, and a kind of situation is that first vibrating device and second vibrating device are used for the detection that pressure changes. Like this, at least one device in first vibrating device and second vibrating device can be used for pressure detecting. As a result, can obtain simultaneously flow-rate measurement and pressure measxurement.

This flowmeter comprises the variable checkout gear, for detection of near the one-component of the AC compounent of the variable waveform zero. Like this, near the null component of this variable, detect a variable, measure so in a time, near null variable, start, in order to implement flow-rate measurement. Therefore, by implementing flow-rate measurement at variable in the little time, even when changing, flow also can make Measurement sensibility.

This flowmeter comprises: frequency detecting device, for detection of the signal frequency of variable checkout gear; And measuring and controlling, this device only when the frequency that is detected by frequency detecting device is preset frequency, just starts and measures. Like this, by only when frequency is preset frequency, just starting measurement, can when predetermined variation occurring, implement to measure. As a result, flow rate that can Measurement sensibility.

This flowmeter comprises detecting cancels device, and this device can start measurement automatically after a predetermined amount of time when not detecting the signal of variable checkout gear. Like this, even after change disappearing, also can when the scheduled time reaches, automatically measure flow rate.

Transmission/reception apparatus and first and second vibrating device comprise piezoelectric sender. Like this, when using piezoelectric sender, ultrasonic wave can be used for transmission/reception, can detected pressures change simultaneously.

Flowmeter of the present invention comprises: transmission/reception apparatus, this device are configured in the stream, are used for utilizing the state of fluid to change to carry out transmission/reception; Duplicating device is used for repeating the signal propagation of transmission/reception apparatus; Time measurement device, the propagation time that is used for measuring the repetitive process of being implemented by duplicating device; The flow rate detection device is used for detecting flow rate according to the measured value of time measurement device; The variable checkout gear is for detection of the changes in flow rate in the stream; Measuring and controlling is used for above each device that these install of control; And the measurement monitoring device, be used for the automatically abnormal conditions of each device of above these devices of monitoring. Like this, when the flow in the stream changes, can according to this measure of the change flow rate, utilize simultaneously and measure monitoring device fast detecting abnormal conditions. Therefore, can correctly carry out the processing of abnormal conditions and make measured value stable. As a result, can measure flow rate in pin-point accuracy ground, and improve the reliability of measuring.

This flowmeter comprises a pair of transmission/reception apparatus, and this device utilizes hyperacoustic propagation to change as the state of fluid. Owing to used ultrasonic wave, so even when flow changes, also can carry out flow-rate measurement. And, can utilize the measurement monitoring device correctly to carry out the processing of abnormal conditions. As a result, can improve the reliability of measurement.

This flowmeter comprises transmission/reception apparatus, and this device utilizes the propagation of heat as the state variation of fluid. Owing to used calorie spread, so even when flow changes, also can carry out flow-rate measurement. And, can utilize the measurement monitoring device correctly to carry out the processing of abnormal conditions. As a result, can improve the reliability of measurement.

This flowmeter comprises: a pair of transmission/reception apparatus, this device are configured in the stream, are used for the transmission/reception ultrasonic wave; Duplicating device is used for repeating the signal propagation of transmission/reception apparatus; Time measurement device is used for measuring hyperacoustic propagation time of repetitive process of being implemented by duplicating device; The flow rate detection device is used for detecting flow rate according to the measured value of time measurement device; The variable checkout gear is for detection of the changes in flow rate in the stream; Measuring and controlling is used for above each device that these install of control; And measurement monitoring device, be used for the abnormal conditions of monitoring enabling signal and the abnormal conditions in the end signal, the first output signal place of the variable checkout gear of enabling signal after the turn signal of measuring and controlling wherein, instruct ultrasonic transmission to begin, end signal instructs hyperacoustic transmission/reception repetitive process to finish at the second output signal place of variable checkout gear. Like this, when the flow in the stream changes, can be synchronized with change frequency and implement to measure, and utilize and measure monitoring device detection abnormal conditions. Therefore, can measure flow rate in pin-point accuracy ground, and obtain reliable measured value. In addition, can correctly carry out the processing of abnormal conditions, and improve the reliability of measured flow rate value.

This flowmeter comprises the measurement monitoring device, when being used for not producing enabling signal in one period scheduled time after measuring and controlling turns to, instructs ultrasonic wave to begin transmission after one period scheduled time. Like this, even when not changing and in the predetermined time section, be not activated signal, also can measure flow rate in each scheduled time, and avoid data degradation.

This flowmeter comprises the measurement monitoring device, when being used for not producing enabling signal in one period scheduled time after measuring and controlling turns to, instructs ultrasonic wave to begin transmission after one period scheduled time. And be used for implementing the measurement of predetermined number of repetition. Like this, even when not changing and in the predetermined time section, be not activated signal, also can carry out in each scheduled time the flow-rate measurement of predetermined number of iterations, and avoid data degradation.

This flowmeter comprises the measurement monitoring device, when being used for not producing enabling signal in one period scheduled time after measuring and controlling turns to, until the next one of measuring and controlling is just measured when turning to. Until next the measurement turns to, can not carry out unnecessary measurement by pausing operation, reduce whereby power consumption.

This flowmeter comprises the measurement monitoring device, when being used for not producing end signal in one period scheduled time after enabling signal, stops hyperacoustic reception. Because hyperacoustic reception is forced to stop, therefore when waiting for end signal, can not suspend measurement. Like this, measurement can proceed to next process, and can implement stable measurement operation.

This flowmeter comprises the measurement monitoring device, when this device does not produce end signal in one period scheduled time after enabling signal, can stop hyperacoustic reception and export enabling signal again. Because hyperacoustic reception is forced to stop, therefore when waiting for end signal, can not suspend measurement. And enabling signal is exported again, thereby remeasures. Like this, can implement stable measurement operation.

This flowmeter comprises the measurement monitoring device, is used for stopping the transmission/reception process when abnormal conditions appear in number of repetition. Because measurement appears having stopped when unusual in number of repetition, therefore only have the data of pin-point accuracy can be used in and carry out flow-rate measurement.

This flowmeter comprises the measurement monitoring device, this device will compare for first number of repetition of measuring and second number of repetition that is used for measuring, and when the difference between first and second numbers of repetition is equal to or greater than pre-determined number, again export enabling signal, wherein in the measurement of using first number of repetition, ultrasonic wave comes out to transmission the first device of transmission/reception apparatus from this, and received by second transmission/reception apparatus, and in the measurement of using second number of repetition, ultrasonic wave transmits from second transmission/reception apparatus, and is received by first transmission/reception apparatus. Like this, when these two numbers of repetition obviously not simultaneously, can re-start measurement, can have whereby the measurement of the pin-point accuracy of steady change frequency.

This flowmeter comprises duplicating device, be used for arranging number of repetition, equate with second number of repetition that is used for measuring for use in first number of repetition of measuring, wherein in the measurement of using first number of repetition, ultrasonic wave comes out to transmission the first device of transmission/reception apparatus from this, and is received by second transmission/reception apparatus, and in the measurement of using second number of repetition, ultrasonic wave transmits from second transmission/reception apparatus, and is received by first transmission/reception apparatus. Like this, by utilizing identical number of repetition, even when change frequency is unstable, also can be scheduled to the measurement of flow rate.

This flowmeter comprises the measurement monitoring device, is used for the number of times that the monitoring enabling signal is exported again, thereby makes the output of enabling signal be confined to pre-determined number or number of times still less, in order to the output of enabling signal can forever not repeated down. Like this, by the number of times that restriction remeasures, can stop measuring process forever to continue. As a result, can carry out stable flow-rate measurement.

This flowmeter is measured flow rate by the difference between the propagation time inverse of surveying, and repeatedly repeats hyperacoustic transmission/reception simultaneously. Like this, when using ultrasonic wave, can in not by the situation of the impact of the change frequency in the stream, carry out transmission/reception. And, measure flow rate by the difference of the inverse in the propagation time of measuring, repeat simultaneously transmission/reception, whereby, can be measured even a macrocyclic variation by some units of one-period. The difference in the propagation time that is caused by variable in addition, can utilize difference reciprocal to offset.

Flowmeter of the present invention comprises: the instantaneous flow rate checkout gear, for detection of instantaneous flow rate; Device is determined in fluctuation, and whether be used for measuring flow rate value has pulse; And at least one or a plurality of stable flow rate calculation element, be used for determining that according to fluctuation the measurement result of device utilizes different device to calculate flow rate value. Like this, by measuring variation and the switch flow rate calculation device in institute's flow measurement rate, can calculate flow rate in reliable mode according to variable quantity by a flow metering device.

Flowmeter of the present invention comprises: the instantaneous flow rate checkout gear, for detection of instantaneous flow rate; Filter processing device is used for carrying out the digital filtering processing of flow rate value; And stable flow rate calculation element, be used for utilizing filter processing device to calculate flow rate value. Like this, when carrying out digital filtering when processing, can carry out the computational process that is equal to mutually with homogenization process, and need not to utilize a large amount of memories to come storage data. And, can by change a variable for example filter factor adjust filtering characteristic.

This flowmeter comprises stablizes the flow rate calculation element, is used for utilizing the digital filtering treating apparatus to calculate a stable flow rate value when fluctuation determines that device mensuration has pulse. Like this, when pulse occurs, select the sharp cut-off filtering characteristic, in order to bigger pulse stable state is provided, and only when pulse occurring, just carries out filtering and process.

Fluctuation determines whether the amplitude of variation of device mensuration flow rate value is equal to or greater than predetermined value. Like this, can measure pulse according to the amplitude of variation of pulse, adjust filtering according to the amplitude of variation of pulse whereby and process.

Filter processing device is adjusted filtering characteristic according to the amplitude of variation of flow rate value. Because filtering characteristic changes according to the amplitude of variation of flow rate value, therefore can the rapid adjustment filtering characteristic, so that abundant relaxation filtering characteristic, this feature so that change hour changes according to the variation of flow rate, and when changing greatly, select the sharp cut-off filtering characteristic, in order to can obviously reduce the flow rate variation that causes owing to pulse.

Only have when the flow rate value that is detected by the instantaneous flow rate checkout gear is low, just carry out filtering and process. Process owing to only when flow rate is low, just carry out filtering, but the therefore variation of fast processing flow rate when flow rate is high, and the influence of fluctuations that causes when flow rate is low is obviously reduced.

Filter processing device is adjusted filtering characteristic according to flow rate value. Because filtering characteristic changes according to flow rate value, therefore only when flow rate is low, just carry out filtering and process, and variation that can the fast processing flow rate when flow rate is high, and the influence of fluctuations that causes when flow rate is hanged down is obviously reduced.

Filter processing device is adjusted filtering characteristic according to the flow rate time interval of instantaneous flow rate checkout gear. Like this, change filtering characteristic by the interval according to the flow rate detection time, can reduce in short-term at the measurement interval variation of relaxation filtering characteristic, and when measuring interval length, reduce the variation of sharp cut-off filtering characteristic.

This flowmeter comprises filter processing device, and this device is adjusted filtering characteristic when flow rate is high, so that the cut-off frequency of filtering characteristic becomes higher, and adjusts filtering characteristic when flow rate is low, so that filtering characteristic has lower cut-off frequency. Like this, response characteristic increases when flow rate is high, and fluctuation reduces when flow rate is low.

Adjust filtering characteristic, so as by the amplitude of variation of the flow rate value of stablize calculating of flow rate calculation element in predetermined range. Because filtering characteristic is adjusted, thereby makes amplitude of variation in predetermined range, therefore can reduces the variation of flow rate, thereby always be equal to or less than predetermined value.

Utilize the ultrasonic flowmeter of ultrasound examination flow rate to be used as the instantaneous flow rate checkout gear. Like this, by utilizing ultrasonic flowmeter, even when bigger flow rate variation occurring, also can measure instantaneous flow rate. Like this, by this flow rate value, can calculate a stable flow rate.

Flowmeter based on heat is used as the instantaneous flow rate checkout gear. When the flowmeter that utilizes based on heat, even when bigger flow rate variation occurring, also can measure instantaneous flow rate. Like this, by this flow rate value, can calculate a stable flow rate.

Control module control cycle changeable device, thus the mensuration frequency of flow rate in measuring in succession changed, measure frequency and do not keep constant in order to make. Like this, when ultrasonic wave was received, the noise synchronous with measuring frequency or hyperacoustic transmission frequency do not gone up mutually same, but has been dispersed. Therefore, can reduce evaluated error.

And flowmeter of the present invention comprises the cyclically-varying device for the driving method that in succession changes drive circuit. The output of response receiving test circuit receives, and control module detects each moment adjustment cycle changeable device of hyperacoustic reception at receiving test circuit, in order to make the mensuration frequency not keep constant. Like this, can in a flow rate determination period, repeatedly set ground operation cycle property changeable device in order to measure. As a result, noise has on average been disperseed in measurement result, thereby can obtain reliable measurement result.

The a plurality of output signals with different frequency of cyclically-varying device switch ground output; And control module changes the set of frequency of cyclically-varying device when each the measurement, thereby changes the driving frequency of drive circuit. Like this, by changing driving frequency, can be changed by the time corresponding with the frequency change that drives signal to receive and detect sequential. Like this, when ultrasonic wave was received, the noise synchronous with measuring frequency or hyperacoustic transmission frequency can not occur mutually same, but has been dispersed. Therefore, can reduce measure error.

The output of cyclically-varying device has same frequency and a plurality of out of phase output signal; And operation control unit so that make the cyclically-varying device output signal be set in mutually each measurement the time change, and the driving of drive circuit is changed mutually. Like this, drive phase by changing, can be changed by the time corresponding with the phase change that drives signal to receive and detect sequential. Like this, when ultrasonic wave was received, the noise synchronous with measuring frequency or hyperacoustic transmission frequency can not occur mutually same, but has been dispersed. Therefore, can reduce measure error.

The cyclically-varying device output composite signal by first frequency signal and second frequency signal are superposeed and obtain, wherein first frequency is the operating frequency of ultrasonic converter, and second frequency is different from first frequency; And control module when each mensuration by output signal of drive circuit output, the second frequency of cyclically-varying device has been changed in this signal. Like this, the cycle that can disturb flow rate to measure. As a result, when ultrasonic wave was received, the noise synchronous with measuring frequency or hyperacoustic transmission frequency can not occur mutually same, but has been dispersed. Therefore, can reduce measure error.

Cyclically-varying device switch has the situation of second frequency and does not have setting between the situation of second frequency. Like this, detect sequential owing to changed reception by the vibration that changes the hyperacoustic ultrasonic converter of transmission, so the periodicity of flow-rate measurement can be disturbed. As a result, when ultrasonic wave was received, the noise synchronous with measuring frequency or hyperacoustic transmission frequency can not occur mutually same, but has been dispersed. Therefore, can reduce measure error.

The cyclically-varying device changes the phase place setting of second frequency. Like this, detect sequential owing to changed reception by the vibration that changes the hyperacoustic ultrasonic converter of transmission, so the periodicity of flow-rate measurement can be disturbed. As a result, when ultrasonic wave was received, the noise synchronous with measuring frequency or hyperacoustic transmission frequency can not occur mutually same, but be dispersed/homogenizing. Therefore, can reduce measure error.

The cyclically-varying device changes the set of frequency of second frequency. Like this, detect sequential owing to changed reception by the vibration that changes the hyperacoustic ultrasonic converter of transmission, so the periodicity of flow-rate measurement can be disturbed. As a result, when ultrasonic wave was received, the noise synchronous with measuring frequency or hyperacoustic transmission frequency can not occur mutually same, but has been dispersed. Therefore, can reduce measure error.

The cyclically-varying device comprises the delay cell that can be set different time delays; And control module is when hyperacoustic each transmission, or each receive to change when detecting postpone to arrange. Like this, in a measurement procedure, the ultrasonic wave reverberation of transmitting in the last measurement that is right after and the hangover of ultrasonic converter impact can be dispersed, and can reduce measure error whereby.

The cycle width that is changed by the cyclically-varying device is several times as much as value corresponding with propagation time variation (this is caused by measure error). Like this, be added and during homogenizing, it is minimum that error can be reduced to when the measured value that is used for all settings.

Equaled a resonant frequency cycle of ultrasonic converter by the cycle width of cyclically-varying device change. Like this, in the value by obtaining for the measured value phase adduction homogenizing of all settings, the measure error that is caused by the hangover of ultrasonic resonance or ultrasonic converter is reduced to minimum. Therefore, can reduce measure error.

Used identical of the figure spectrum level that is used for the change cycle and the measurement of the measurement of updrift side and downstream direction. Like this, the hyperacoustic measurement that has upstream side transmission is always carried out under identical condition with the hyperacoustic measurement with downstream side transmission. As a result, even when flow rate changes, also can access reliable measurement result.

Predetermined number of times is several times as much as the change frequency of cyclically-varying device. Like this, all setting values of cyclically-varying device all are arranged in the flow-rate measurement operating process equably. As a result, can access reliable measurement result.

In addition, utilize second timer to measure the time period that detects next clearing time from reception, use whereby the resolution ratio higher than first timer to measure. And, comparing with the flowmeter with equal resolution, its power consumption has reduced, and this is because only operate second timer in the short period section that receives after detecting.

And owing to proofread and correct second timer with first timer, therefore second timer only need have short-term stability. So, need not to use particular component. Therefore, be easy to obtain high-resolution timer.

And, owing to when the output of temperature sensor changes, proofread and correct second timer with first timer, therefore thereby make it be equal to or higher than setting value, even when second timer has the characteristic that varies with temperature and change, also can use flowmeter of the present invention.

Moreover, owing to when the output of voltage sensor changes, proofread and correct second timer with first timer, therefore thereby make it be equal to or higher than setting value, even when second timer has the characteristic that changes with voltage change, also can use flowmeter of the present invention.

Flowmeter of the present invention comprises: the flow rate determination unit, treat fluid measured this unit of can flowing through; A pair of ultrasonic converter, this converters are used for the transmission/reception ultrasonic wave in the flow-rate measurement unit; Be used for driving the drive circuit of one of ultrasonic converter; Link to each other with another ultrasonic converter, for detection of the receiving test circuit of ultrasonic signal; Control module, this unit are used for pre-determined number ground control drive circuit, again drive ultrasonic converter in order to respond the output of receiving test circuit; Be used for pre-determined number ground and measure the timer of process time; Be used for being calculated by the output of timer the computing unit of flow rate; And being used for the cyclically-varying device that order changes the driving method of drive circuit, control module control cycle stabilising arrangement wherein is in order to make frequency always keep constant. This structure has been arranged, even when the propagation time changed, measuring frequency was also always constant. Like this, when ultrasonic wave was received, the noise synchronous with measuring frequency or hyperacoustic transmission frequency always occurred mutually same, and no matter whether the propagation time changes. Therefore, measure error can keep steady state value. As a result, even when noise has the very long cycle, also can make the flow-rate measurement stabilisation.

This control module comprises the periodicity stabilising arrangement that is formed by the delay cell that can be set different time delays; And control module changes the output timing of drive circuit by the switching delay number of times.Owing to make time delay survey frequency keep constant by changing, so survey frequency can be stabilized, and can not influence the driving of ultrasonic converter.

The control module control Driver Circuit is so that make Measuring Time keep constant.Like this, it is constant that survey frequency can keep, and only need simple calculating, the travel-time that need not to calculate each ultrasonic transmission.

Claims (11)

1. flowmeter comprises:

The instantaneous flow rate pick-up unit is used for the instantaneous flow rate of test fluid;

Filter processing is used for handling by the detected fluid instantaneous flow rate of instantaneous flow rate pick-up unit being carried out digital filtering, comes the pulse flow rate component in the filtering fluid instantaneous flow rate; And

Stablize the flow rate calculation element, be used for coming the stable flow rate of Fluid Computation according to the output of filter processing.

2. flowmeter according to claim 1 also comprises the definite device of fluctuation, is used for determining whether the instantaneous flow rate of fluid exists pulse,

Wherein, when fluctuation determines that device determines that there is pulse in the instantaneous flow rate of fluid, stablize the flow rate calculation element comes Fluid Computation according to the output of filter processing stable flow rate.

3. flowmeter according to claim 2, wherein, fluctuation determines whether device is equal to or greater than predetermined value by the amplitude of variation of determining the fluid instantaneous flow rate and determines whether the instantaneous flow rate of fluid exists pulse.

4. flowmeter according to claim 1, wherein, filter processing is adjusted filtering characteristic according to the amplitude of variation of fluid instantaneous flow rate.

9. flowmeter according to claim 1, wherein, filter processing is adjusted filtering characteristic, makes by the amplitude of variation of stablizing the stable flow rate that the flow rate calculation element calculates in a predetermined range.